ECVET Vegetable Gardening Pest Management

ECOGARD
IO2: Training course on ecological vegetable gardening (ECVET
based) for the students with learning/cognitive disabilities
Unit 5. Pest Management in Ecological
Vegetable Gardening
Supporting access to training and qualification of
people with disabilities through development of VET course on
Ecological Vegetable Gardening based on ECVET learning outcomes
2017-1-BG01-KA202-036212

Module 5. Pest Management in Ecological
Vegetable Gardening
Summary:
The module provides information about the diseases of vegetables
and the insects that may affect the yields in vegetable production.
The trainees will also get knowledge about the general plant
protection methods applied against diseases and insects in
ecological (organic) cultivation of vegetables.
Further, a comprehensive information will be provided about the
legislation concerning pests management and control methods
applied in organic farming in Bulgaria, Slovenia and Turkey.

5.1. Introduction to the pest management in
ecological vegetable gardening
Pest management measures in terms of organic (ecological) vegetable
gardening is a difficult task and requires extensive experience and
long-term vision.
Pests (insects, diseases and weeds) cause the most serious problems
in vegetable production, significantly reducing their market value.
Therefore, vegetable crop protection, which focuses on prevention, is
of particular importance for organic farming.
The purpose of the pest control in organic farming is not to wipe out
pests (insects, diseases and weeds) but to control/manage them.

5.1. Brief introduction to diseases causing
problems on vegetable crops (tomato,
pepper, cucumber, potatoes, onion
2017-1-BG01-KA202-036212
Tomatoes are attacked by many diseases - viral, bacterial and fungal.
Some of them damage tomatoes grown in cultivation facilities (greenhouses), others -
in open-air cultivation, and most of them attack tomatoes in greenhouses and on the
field. Diseases with greater economic importance are listed below.

Viral tomato diseases
More than 20 viruses affect tomatoes worldwide, causing a wide variety of mosaic patterns and
distortions to the leaves, stunted growth and marbling patterns on the fruit, whenever the
plants are growing from late winter until early autumn.
The most common tomato viruses in Bulgaria are:
1. Tobacco mosaic virus (TMV)
2. Tomato mosaic virus (ToMV)
3. Tomato spotted wilt virus (TSWV)
4. Cucumber mosaic virus (CMV)
Tomatoes are attacked by many diseases - viral, bacterial and fungal.
Some of them damage tomatoes grown in cultivation facilities (greenhouses), others - in open-air
cultivation, and most of them attack tomatoes in greenhouses and on the field. Diseases with greater
economic importance are listed below.

Symptoms of viral diseases
You may see the following symptoms:
 Stunted growth and reduced yield are common symptoms, especially when several
viruses are present
 Mosaic patterns of lighter green on the leaves (TMV, ToMV, CMV)
 Fern leaf, where the leaf blade is reduced in size to give a fern-like appearance
(TMV, CMV)
 Brown streaked leaves (TMV)
 Young leaves curl downwards and become bronzed (TSWV)
 Dry set, when fruit fail to set (TMV)
 Fruit develop a bronzed, patchy appearance (TMV, ToMV)
 Fruit ripens unevenly with pale patches or marbling (TSWV)

Vectors
 CMV is vectored by aphids
 TSWV is vectored by thrips, especially the western flower thrips
 TMV is very easily spread mechanically on tools or fingers
 TMV is occasionally transmitted through seed
 Several of these viruses have other common garden host plants. CMV
has a very wide range of hosts, not only among cucurbits. TMV also
affects tobacco and potato. TSWV affects many plants in the tomato
family (Solanaceae.

Tomato viral diseases
Tobacco mosaic virus (TMV)
Tomato mosaic virus (ToMV)

Tomato viral diseases
Tomato spotted wilt virus

Fungal diseases
 Verticillium Wilt - Verticillium albo-atrum
 Early Blight - Alternaria solani
 Powdery Mildew on Tomatoes – Botrytis cinerea
 Fusarium Wilt – Fusarium oxysporum t.sp. Lycopersici
 Late Blight of Tomato (Phytophthora infestans)

Verticillium Wilt - Verticillium albo-atrum
 Symptoms: Yellow blotches appear on the lower leaves.
As the blotches spread, the veins in the leaves turn
brown. After the leaves turn brown, they fall off. The
disease progresses up the stem until the plant is
stunted.
 Causes: A fungus that lives in the soil, Verticilliurn albo-
atrum, attacks the roots and travels up the xylem tubes
with water. It then prevents the normal flow of water
and nutrients to the leaves.
 Control: Once plants are infected, there isn’t much you
can do to treat Verticillium wilt. Rotate your crops,
because the fungus can live for long periods in the soil
and even live among weeds such as ragweed. Choosing
wilt-resistant varieties to plant is the best way to
prevent Verticillium wilt.
https://www.sciencephoto.com/media/b2800012/view
Fungal diseases

Early Blight - Alternaria solani
 Symptoms: Brown spots on tomato leaves, starting with the
older ones. Each spot starts to develop rings, like a target.
Leaves turn yellow around the brown spots, then the entire
leaf turns brown and falls off. Eventually the plant may have
few, if any, leaves.
 Cause: A fungus called Alternaria solani. This fungus can live
in the soil over the winter, so if plants have had problems
before like this, and you’ve planted tomatoes in the exact
same spot, chances are good the same thing will happen to
your plants this year.
 Control: Crop rotation prevents new plants from contracting
the disease. Avoid planting tomatoes, eggplants or peppers in
the same spot each year as these can all be infected with
early blight.

https://www.infonet-biovision.org/PlantHealth/Pests/Early-blight
Early blight on tomato leaflet. Note concentric rings in
the spots. A. M. Varela, icipe

Powdery Mildew on Tomatoes – Botrytis cinerea
 Symptoms: Powdery mildew is easy to find on tomato plants
as it looks like someone brushed the leaves with a white
powder. You might find white spots on tomato leaves or
even the stem. If you let the fungi thrive it will turn your
tomato leaves yellow and then brown.
 Cause: Powdery mildew on tomatoes is more common in
greenhouses than an outdoor garden because of the lack of
air flow and high humidity.
 Control: The best way to prevent powdery mildew on
tomato plants is to use a preventative spray formulated
with sulfur allowed to be used in organic vegetable
production.
https://www.slideshare.net/acornorganic/v3-organic-control-options

Fusarium Wilt – Fusarium oxysporum t.sp. Lycopersici
 Symptoms: Tomato plants look fine, when suddenly, they start
to wilt. At first, only one side may be affected, but then the
whole plant is wilting. When you water them, the problem
gets worse. Within a day or two, the plant is dead!
 Causes: A nasty fungus called Fusarium oxysporum f.sp.
lycopersici that attacks the vascular system of the plant,
roughly equivalent to a human’s veins. The fungus destroys the
xylem tubes, which transport water and nutrients up from the
roots and into the leaves.
 Control: In the case of fusarium wilt, the best defense is a
good offense. Rotate your crops so tomatoes aren’t planted in
the same section of the garden each year. Purchase wilt-
resistant varieties if you’ve lost tomatoes to wilting diseases in
the past, since the fungus can overwinter in garden and lawn
soils.
http://ephytia.inra.fr/fr/D/769

Late Blight of Tomato (Phytophthora infestans)
Symptoms: On tomato leaves lesions begin as indefinite, water-soaked
spots that enlarge rapidly into pale green to brownish-black lesions and
can cover large areas of the leaf.
On tomato petioles and stems lesions begin as indefinite, water-soaked
spots that enlarge rapidly into brown to black lesions that cover large
areas of the petioles and stems. During wet weather, lesions may be
covered with a gray to white moldy growth of the pathogen. Affected
stems and petioles may eventually collapse at the point of infection,
leading to death of all distal parts of the plant.
On tomato fruits dark, olivaceuos greasy spots develop on green fruit; a
thin layer of white mycelium may be present during wet weather.
https://www.google.com/search?q=Late+Blight
+of+Tomato+(Phytophthora+infestans)&source=l

Bacterial diseases on tomatoes
Bacterial Canker – Clavibacter michiganense
 Symptoms: Often confused with cloudy spot disease, bacterial
cankers start as yellow dots on ripening red tomatoes. If you look
carefully at the spots — using a magnifying glass if you have one —
you’ll see a dark, birds-eye-type rim around each of the yellowed
spots. This is what distinguishes bacterial canker from cloudy spot
disease.
 Pathogen: A bacteria called Clavibacter michiganensis. The
bacteria occurs naturally but can be brought into the garden on
infected plants or tools. Once it gets into the soil, rainwater
splashes it up onto the plants. If there’s an open sore, such as
insect damage or a leaf missing from pruning, it can enter the
plant and infest it.
 Control: Remove the infected plants immediately and do not plant
tomatoes again in that soil for at least three years. Rotate your
crops regularly to prevent these and other diseases from taking
hold in the soil. Don’t compost the dead plants — instead, put
them in the trash to avoid spreading the bacteria.
https://www.koppertus.com/challenges/disease-control/bacterial-
canker-of-tomato/
https://www.google.com/search?q=Bacterial+Canker+–
+Clavibacter+michiganense&tbm

Bacterial wilt – Pseudomonas solanacearum
Bacterial wilt is one of the major diseases of tomato and
other solanaceous plants.
Pathogen: The disease is caused by the bacterium Ralstonia
solanacearum, previously known as Pseudomonas solanacearum. It is
one of the most damaging plant pathogens. Strains of this pathogen
affect more than 200 plant species in over 50 families throughout the
world, including a wide range of crop plants, ornamentals and weeds.
Symptoms:
At the early stages of disease, the first visible symptoms of bacterial
wilt are usually seen on the foliage of plants. These symptoms consist of
wilting of the youngest leaves at the ends of the branches during the
hottest part of the day.
At this stage, only one or half a leaflet may wilt, and plants may appear
to recover at night, when the temperatures are cooler. As the disease
develops under favorable conditions, the entire plant may wilt quickly
and desiccate although dried leaves remain green, leading to general
wilting and yellowing of foliage and eventually plant death. Another
common symptom that can be associated with bacterial wilt in the field
is stunting of plants. These symptoms may appear at any stage of plant
growth, although in the field it is common for healthy-appearing plants
to suddenly wilt when fruits are rapidly expanding.
https://plantpath.ifas.ufl.edu/rsol/trainingmodules
/bwtomato_module.html
Bacterial diseases

Control
 Remove plants with symptoms promptly;
 After handling infected plants, wash hands and tools in hot soapy
water;
 Avoid growing other susceptible plants in close proximity;
 Varieties with claimed resistance to viral diseases.

The most common cucumber viral diseases in Bulgaria are:
1. Tobacco mosaic virus (TMV)
Pepper grown in cultivation facilities and outdoors is attacked by many
diseases. Some of them have greater economic significance for greenhouse
production, others for the Polish. Viral, fungal and bacterial
pathogens cause damages on pepper. They attack roots, leaves, stems and
fruits and can cause significant reduction in yields.
Viral pepper diseases

Tobacco mosaic virus (TMV)
 Symptoms: Tobacco mosaic virus is not as distinct as
other viruses, but yellow-green mottling on leaves is the
most characteristic symptom of the disease. Infected plants
have stunted growth, and flowers and leaflets may be
curled, distorted, and smaller than normal in size. Open
blooms may have brown streaks through them. Yellow,
chlorotic spotting is characteristic of pepper plants that are
infected.
 Pathogen: Tobacco mosaic virus survives on infected
seeds, plant debris, and even clothing for months or years.
The virus enters plants through wounds sustained in
transplanting or pruning. It spreads rapidly once it is in the
host. The virus can remain viable for years on dried plant
debris and is extremely tolerant of very high temperatures.
The virus is not spread by aphids.
 Control: Remove and destroy infected plants. Pull plants
with mosaic symptoms immediately. Remove the debris
from the garden area and bury them if possible. Always
wash your hands thoroughly and disinfect tools. Plant
resistant varieties of pepper.
Viral diseases

Cucumber mosaic virus (CMV)
Symptoms: They vary widely. One of the most common expressions is a severely stunted,
nonproductive plant that has dull light green foliage with a leathery appearance but not distinctive
foliar markings. In some cases the leaves become narrow and no longer expand, while in other cases,
small necrotic specks or ring spots with oak leaf patterns develop. Sometimes a necrotic line develops
across the leaf. Affected leaves may drop prematurely. Older plants that are infected may show foliar
mottling or no symptoms on foliage or fruit. Fruit may be wrinkled, bumpy, pale to yellowish green in
color, sometimes with sunken lesions. On some varieties lines or ring spots may develop.
Control: Plant pepper resistant varieties. Control measures for CMV are mainly preventive due to the
wide host range of the virus and the numerous aphid vectors. Vegetable seedlings, other than pepper,
derived from CMV-infected seeds can also serve as potential primary sources of virus. The use of virus-
free seeds together with the eradication of virus reservoirs such as volunteer plants and nearby weeds
can be effective in controlling CMV.
Remove diseased plants from the field as soon as virus symptoms are noticed. This will reduce the
spread of the virus by aphid vectors.
Prevent aphids from reaching the pepper crop by covering the planted area with fine 32-mesh nylon
net.
Viral diseases

Cucumber mosaic virus (CMV) on pepper
Viral diseases

Fungal disease
Phytophthora Blight - Phytophthora capsici
Symptoms: Infection of the stem near the soil line is common. Stem lesions start as
dark, water-soaked areas which become brown to black and result in girdling, wilting and
plant death. Phytophthora capsici may also cause root rot and foliar blight on pepper. On
leaves, small, water soaked lesions expand and turn a light tan colour. White moldy growth
may be seen on leaves during wet periods. Rapid blighting of leaves and shoots may occur.
Pepper fruit can also be infected through the fruit stalk. Fruit rot appears as dark green,
water-soaked areas that become covered with a white to gray mold. Infected fruit dries,
becomes shrunken and wrinkled, and remains attached to the stem.
Pathogen: Phytophthora blight on peppers is caused primarily by the pathogen
Phytophthora capsici.
P. capsici is spread through movement of soil or by water running through an infested area.
The pathogen is also spread by wind or splashing water as spore-like structures called
sporangia. Sporangia can either germinate directly and infect pepper tissue, or they can
produce several swimming spores (zoospores) that spread over the plant surface in films of
water and initiate multiple infections.
This pathogen has a wide host range. It is able to cause disease on a number of
solanaceous crops, including pepper, eggplant, and tomato, as well as cucurbitaceous
crops including cucumber, squash, pumpkin, watermelon,and muskmelon.

Phytophthora blight on pepper - Phytophthora capsici
Fungal disease

Bacterial disease
Bacterial spots - Pseudomonas syringae pv. Syringae
Symptoms: This pathogen can cause severe spots and yellowing on
pepper foliage. Although symptoms can initially look very severe, once
conditions become less favourable for the pathogen new growth is
unaffected. Not known to cause fruit lesions or have an economic impact.
Bacterial spot on peppers first appears as small, water-soaked areas on
the undersides of leaves. These areas can quickly enlarge into spots that
are up to ¼ inch in diameter, turn dark brown and become slightly raised
(Figure 1). On the upper sides of leaves, the spots are slightly depressed
with brown borders and beige centers. Infected leaves turn yellow and
drop prematurely. This defoliation can expose developing fruit to
sunscald, and the loss of leaves reduces the plant’s ability to adequately
support fruit development.
The pathogen can also infect the fruit, and there are significant losses
from the shedding of blossoms and abortion of developing fruit. Any
remaining fruit may not be marketable due to small size, deformities, and
brown, circular lesions. The spot bacteria do not rot fruit directly, but
lesions on fruit can provide an entrance for other fruit rotting pathogens,
resulting in fruit decay.

The most common potato viral diseases in Bulgaria are:
1. Potato virus X (PVX)
2. Potato virus Y (PVY)
Potatoes are attacked by a significant number of diseases. The most
important are the viral and fungal diseases.
Viral potato diseases
Fungal potato diseases
The most common potato fungal diseases in Bulgaria are:
1. Phytophthora infestans
2. Alternaria porri f.sp. solani

Potato common mosaic virus – Virus X (PVX)
Viral diseases
Caused by the potato X virus. Carries contact by touching healthy
with diseased plants. Not carried by insects.
The infected plants are mosaic scaly leaves. Growth is poorly
affected, but yields decrease by an average of 10-15%.
When mixed with other viruses, losses are significantly increased
in sensitive varieties.

Viral diseases
Potato Virus Y (PVY) in Potato – leaves curling and black pox
Potato Virus Y (PVY) in Potato
(Family Potyviridae)
(Pictures courtesy of Nan Jing Ko)
Symptoms of the
mosaic strain of PVY
in potato
Cylindrical nclusions (CI) of PVY in
potato epidermis
Symptoms of the
necrotic strain of PVY
in potato
Symptoms are curly, mosaic, dark necrotic stains.
The cause is Y virus, which is transmitted by aphids.

Fungal disease
Late Blight of Potatoes (Phytophthora infestans)
Late blight of potato is the most
important fungal disease in potatoes. It
attacks all overground parts of plants in
phase-blossoming. Large, watery, chlorotic
spots, covered with a loose, white sporadic
scratch on the bottom, appear on the lower
leaves. In case of a strong attack, the plants
are defoliated and wither.
When harvesting sick tubers are hard to
recognize. The first signs appear after 2-3
weeks in the form of sunken, irregularly
shaped lead-gray spots.

The most common cucumber viral diseases in Bulgaria are:
2. Cucumber mottle mosaic virus
3. Beet pseudo-yellows virus
Cucumbers grown in greenhouses and outdoors are attacked by many diseases, the
majority of which are of great economic importance to the crops grown and the yield
obtained. There are viral, fungal and bacterial diseases. They attack the roots,
the stems, the leaves, and sometimes the fruits.
Viral cucumber diseases

 The disease, cucumber mosaic, is caused by
the Cucumber mosaic virus (CMV). CMV is one of
the most common and destructive cucurbit viruses,
and it is widely distributed throughout temperate
and tropical areas of the world.
 CMV can infect over 1200 plant species including
both monocots and dicots.3 There are many strains
of CMV that differ in the symptoms they cause, the
range of hosts they infect, and their means of
dispersal.4 Yield losses of 10 to 20% are common,
and losses of up to 100% can occur.
Figure 1. Mosaic symptoms oncucumber leaves andfruit fromCMVinfection.
Viral diseases

 Cucumber plants can be infected with CMV at any stage, and once a plant is infected the virus
spreads systemically within the plant. Symptoms appear 7 to 14 days after infection. A light- to
dark-green mosaic or mottling appears first on the youngest leaves (Figure 1). New leaves are
stunted and distorted with the outer edges curling downward. Plants are stunted, sometimes
severely, with shortened internodes resulting in a bushy canopy. Flowers can show abnormal
features such as green petals. Fruit produced on infected plants are often smaller and somewhat
deformed, and show mosaic patterns of light and dark green on the skin.
 Many crop-, ornamental-, and weed-species can serve as reservoir hosts of CMV. Some common
weed hosts include bur-cucumber, burdock, common milkweed, horsenettle, jimsonweed, marsh
yellowcress, nightshades, pigweed, pokeweeds, white cockle, and wild-cucumber. Perennial hosts,
such as alfalfa, are important reservoir hosts of CMV in regions with cold winters.
 The severity of CMV epidemics depends on the number of aphids present and the number of
infected reservoir hosts. Aphid numbers tend to be higher when conditions are warm and dry.
https://www.growveg.co.uk/plant-diseases/uk-
and-europe/cucumber-mosaic-virus/
Viral diseases

Cucumber mottle mosaic virus
 Cause: Green English mottle mosaic is caused by Cucumber mottle mosaic virus.
Transported with seeds up to 8-10%, which is sufficient for an initial infection as well as
juice from diseased plants. In hydroponic cultivation the attack rate can reach up to
80%. No transfer of lice or other sucking insects has been detected.
 Life Cycle: The virus is kept until the next vegetation in plant soil in the soil. It quickly
penetrates the plants. The first symptoms appear on the youngest, rising leaves.
Sprouted plants of infected seeds are also infected. It also infects the soil. Therefore,
seeds are of great importance in the pathogenesis of the virus. They are the main source
and the possibility of spreading it on new plots. It is transported by hand manipulation of
plants, even in contact with patients with healthy plants. Easily spreads with irrigation
water and soil treatment.
Viral diseases

Cucumber mottle mosaic virus
 In Bulgaria, the virus was first established in 1971. After its mass
distribution in the country's greenhouses, it later diminished and its
economic importance diminished.
 Symptoms: The first signs appear on the top leaves of the plants. They
are heavily mosaic scattered by alternating dark green and light green
(sometimes even yellow-green) areas. In bright areas the growth of the
leaves stops, and the green leaves. As a result, their surface is pricking, it
becomes rough and creased. Sometimes only the veins remain green.
Fruits are also gray, their surface rough, unevenly growing areas. The
diseased plants are lagging behind in their growth. The virus is inactivated
when the leaves become old. The yield decreases 2 25% and sometimes
more.
Viral diseases

Beet pseudo-yellows virus
 Beet pseudo-yellows virus in cucumbers is spread all over the
world and has a wide range of hosts. In Bulgaria, the virus was
first established in 1983.
 Symptoms: Beet pseudo-yellows is an important disease on
greenhouse cucumber and muskmelon (cantaloupe). This virus
was previously known as cucumber yellows or muskmelon
yellows. Symptoms first appear on older leaves as yellow spots
which develop into yellow blotchy raised areas between veins,
while the veins themselves remain green. These raised areas
eventually coalesce to form large thickened areas, which become
brittle and may disintegrate. As the disease progresses, younger
leaves begin to develop symptoms, but fruit remain unaffected.
Plants infected at an early stage can be stunted and may have
fewer fruit. Symptoms caused by beet pseudo-yellows can easily
be confused with symptoms resulting from nutritional
deficiencies (e.g., magnesium), insect feeding, poor growing
conditions and premature aging.
Source: https://aggie-horticulture.tamu.edu/vegetable/files/2011/11/beetyellows2.jpg
Viral diseases

Beet pseudo-yellows virus
 Cause: It is the Beet pseudo-yellows virus, which is transported from the
Greenhouse whitefly (Trialeurodes vaporariorum).
 Life Cycle: The greenhouse whitefly can acquire and transmit Beet pseudo-
yellows virus in a semi-persistent manner. Symptoms begin to develop two to
four weeks after infection. The virus is not seed-borne or mechanically
transmitted. High light intensity appears to be necessary for disease
development. This virus has a large host range among crops and weed
species. In addition to cucumber, muskmelon (cantaloupe) and squash, BPYV
also infects many ornamentals and other vegetable crops such as lettuce,
endive, carrot, spinach and beet.
Viral diseases

Downy Mildew, Peronospora destructor (Berk.)
Symptoms:
 Oval or cylindrical areas of varying sizes develop on infected leaves and seed stalks.
These areas are pale greenish-yellow to brown in color. Symptoms often appear first on
older leaves. If weather conditions are moist and temperatures are low, masses of gray
to violet fungal spores envelop infected leaves, which become girdled, collapse, and
die. The dead leaf tissue is rapidly colonized by purple blotch, which is dark in color
and obscures downy mildew.
 Downy mildew seldom kills onion plants, but bulb growth may be reduced. Bulb tissue,
especially the neck, may become spongy and the bulb may lack keeping quality. This
disease is one of the most destructive of onion seed production world-wide.

Downy Mildew, Peronospora destructor (Berk.)
Disease Cycle:
 The downy mildew fungus can rest in perennial varieties and in
infected onion bulbs left in the field and in cull piles. Resting sexual
spores (oospores) may persist in the soil to infect seedling onions
planted the following season. During the onion growing season the
fungus produces spores (conidia) that are carried by wind to infect
new onion plants. Spores are produced on nights with high humidity
and moderate temperatures (4-25° C) with an optimum
temperature for sporulation of 13° C. The spores mature early in
the morning and are dispersed during the day. They remain viable
for about 4 days. For germination the spores require free water and
the optimal temperatures 7-16° C. Rain is not needed for infection
when dew occurs continuously during the night and morning.
 After the fungus is established, it completes its life cycle in 11 to
15 days. New spores infect new plants or leaves. As the upper
portion of the onion leaf is killed, the fungus can infect the next
lower part of the leaf. The entire leaf may thus become infected
and die. During favorable environmental conditions the infection
may result in a severe epidemic. During dry weather, the spores
usually disappear and the number of lesions declines. However, the
disease cycle recommences when wet, cool weather recurs.
http://web.entomology.cornell.edu/shelton/veg-insects-global/graphics/dmildew/dmildew1gif.html

5.1. Brief introduction to insects causing
problems on vegetable crops (tomato,
pepper, cucumber, potatoes, onion) grown
on open field
2017-1-BG01-KA202-036212

INSECTS ATTACKING TOMATOES
Tuta absoluta
 Tuta absoluta is a very harmful leaf mining moth with a strong preference for tomatoes. It occurs on
eggplants, sweet peppers as well as potatoes and various other cultivated plants. It also occurs on
weeds of the Solanaceae family (Solanum nigrum, Datura spp.). Tuta absoluta can cause 50-100%
yield reduction on tomato crops and its presence may also limit the export of the product to several
destinations.
Biology
 Tuta absoluta reproduces rapidly, with a life cycle ranging from 24-38 days, depending on
temperature. The minimum temperature for activity is 9°C. Its larval stage (caterpillars) does not
enter diapause as long as food is available. One female may deposit up to 250-260 eggs during her
life which are deposited on plant parts above ground. Eggs develop into a caterpillar, mining inside
the leaf, stem or fruit but exit to pupate.
There are four larval instars. In between moulting, caterpillars can temporarily be found outside the leaf
mines or fruit. Pupation may take place in the soil or on the surface of a leaf, in a curled leaf or in a
mine. Overwintering can take place as egg, pupa or adult moth. Moths are active during night and hide
between leaves during day.

Tomato leaf mining moth - Tuta absoluta Meyrick
Source: http://www.hortidaily.com/article/32669/Tuta-Absoluta-
remains-risk-for-Dutch-organic-tomato-growers
https://www.youtube.com/watch?v=4MMu0c_m7UY
Video: Life cycle of Tuta absoluta (tomato leaf mining
moth)
Source: https://www.koppert.com/pests/tuta-absoluta/

Damage
 Caterpillars prefer leaves and stems, but may also
occur underneath the crown of the fruit and even
inside the fruit itself. The caterpillars attack only
green fruit.
 Most distinctive symptoms are the blotch-shaped
mines in the leaves. Inside these mines both the
caterpillars and their dark frass can be found.
 In case of serious infection, leaves die off
completely.
 Mining damage to the plant causes its malformation.
Damage to fruit allows fungal diseases (for example)
to enter, leading to rotting fruit before or after
harvest.

Cabbage moth - Barathra (Mamestra) brassicae L.)
 Damage: Caterpillars damage cruciferous plants,
especially cabbage, leguminous cultures, and sugar
beet. Prefer crucifers.
 Caterpillars of 1st instar skeletonize leaves from below,
leaving upper epidermis untouched; larvae of 2nd-3rd
instars gnaw out apertures. Caterpillars of older instars
are nocturnal, hiding at the base of plants in the
afternoon. They eat leaves almost completely, leaving
only thick veins. Also, they make holes in the plant
head, polluting it with excrements, and the head rots.
 Control measures include autumn plowing, inter-
row cultivation of tilled cultures, eradication of weeds,
release of Trichogramma in the beginning of moth flight
and repeatedly for 7-8 days, and bio-insecticide
treatments of plants during the period of caterpillars
hatching.
http://www7.inra.fr/hyppz/RAVAGEUR/6mambra.htm

Cabbage fly – Delia brassicae

Onion fly - Delia (Chrotophila, Hylemyia) antiqua
Source:
http://www.agroatlas.ru/en/content/pests/
Delia_antiqua/index.html
Source:
http://enacademic.com/dic.nsf/enwi
ki/11629393
Source: http://agronomija.rs/2013/lukova-muva-hylemya-antiqua-
delia-antiqua/

Garlic fly - Suilia lurida Meig.
Source: http://www.ukrup.com.ua/en/garlic-
fly-pest-of-winter-garlic/

5.3.2. Introduction to some economically
important insects on vegetable crops
in greenhouses
2017-1-BG01-KA202-036212

Whitefly - Trialeurodes (Asterochiton) vaporariorum Westm.

Class Nematoda
Root Knot Nematodes – Genus Meloidogynae
Source: http://www2.palomar.edu/users/warmstrong/pljuly99.htm

Under field conditions, the control of rot-knot nematodes is
mainly carried out by agro-technical methods.
The vegetable crops should be grown on soils clean from nematode.
When sowing susceptible varieties or suspicion of contamination, a soil analysis is
required (by well-trained specialists).
It is very efficient to implement crop rotation by introducing crops which are not
attacked by nematodes. (wheat).
In case of poorly attacked crops, optimal conditions for the development of the crop
(irrigation, etc.) should be provided to overcome the damage and obtain a normal
yield.

Using repellent plants for Nematode Control
Source: https://www.gardeningknowhow.com/plant-problems/pests/insects/nematode-control-with-plants.htm
Control: Some nematodes can be controlled using nematode-killing pesticides
(nematicides), but these can be toxic and most are unavailable to home gardeners.
Crop rotation can also reduce nematode infestations, but it is time consuming.
Fortunately, scientists have identified a list of nematode repellent plants that can help
combat these earth-dwelling pests. These include:
Painted daisyDahliaFrench Merigold

Using repellent plants for Nematode Control
 Marigolds release a natural compound
into the soil which is toxic to root knot
nematodes. If you plant marigolds as a
cover crop between plantings of food
crops, you may see a slow and gradual
reduction in root knot nematode activity.
This works cumulatively in the soil.

Greenhouse protection
Bioagents for protection of greenhouse vegetable crops approved
for organic farming:
Predatory mite Phytoseiulus persimillis

5.2. How to deal to prevent diseases
and pests in ecological vegetable
gardens?
2017-1-BG01-KA202-036212

Principles and strategy of plant protection
 Organic and conventional agriculture have a common goal: to grow and
maintain crops under healthy conditions.
 To achieve this, conventional agriculture requires synthetic substances -
pesticides that violate the balanced state of agro- ecosystems and makes
them more dependent on these chemicals.
 Farmers practicing organic farming renounce the use of chemical
pesticides. They can use a limited set of approved pesticides of plant or
mineral origin, but their effectiveness is very low compared with the
efficiency of modern pesticides.

 The main objective of biological plant protection is to eliminate
the causes of the occurrence of harmful organisms. The main
objective of biological plant protection is to eliminate the causes
of occurrence of pests , i.e. application of preventive measures or
the so called indirect methods of plant protection. Therefore,
only if harmful organisms proliferate over maximum levels shall
direct methods of protection apply.
 In organic farming a balance must be maintained between pests
and their antagonists.

Principles and strategy of plant protection
Methods of plant protection in organic farming
Indirect methods Immediate / direct methods
Focusing on prevention and resilience
provided by:
- Balanced plant nutrition
- Cultivation of suitable plant species
and their diversification
- Choice of varieties
- Appropriate methods of cultivation
- Using the positive effect of different
plant species on each other
Physical:
- Mechanical
- Thermal (not optional)
Biological control
Limited number of plant protection
products on plant and mineral-based
Products based on normal sulfur and
copper compounds (total volume per
hectare is limited)

Indirect methods of pest management:
prevention / precautions
Care of soil fertility and biodiversity
 One of the main properties of natural soil is its ability to reduce the incidence
of diseases. This is a very important condition for organic farming. Plants,
grown in biologically active soil receive natural resistance (endurance) to pests.
 Living organisms have natural enemies. Absence or low numbers of beneficial
organisms in the environment creates the disastrous expansion of the density of
pests and diseases. Therefore, in addition to strong and bioactive soil essential
in agro- ecosystems is the diversity of life forms (biodiversity). This is a
prerequisite for the ability of the system to cope with the spread of diseases
and pests (so-called buffer function of biodiversity).

Crop rotation - as regards to measures against latent and active stages of
development of pathogens is oriented towards:
- Exclusion of the plants - the host of the cultivation (i.e., by rotation ), thereby
to break the cycle of development of the pathogen .
- Violation of the latent stages of pathogens, so that they appear at the wrong
time for their development.
If crop rotation is not accompanied by other measures, it can not guarantee enough
reduction of the infectious potential of the soil.
Selection of a suitable location – with the right choice in site selection the
productive capacity of the plants is best observed. To expect them to obtain high and
stable yields , soil and climatic conditions shall be in accordance with the
requirements of the crop. If plants do not receive optimal conditions for their growth
and development , they become more susceptible to attack by pests - diseases and
pests .

 Choice of varieties - an important prerequisite for effective
control of diseases and pests, as a stronger and less preferred (
attacked ), tolerant and partially resistant varieties. Most promising
are recent. Example of resistant varieties are bred potato varieties
resistant to potato cyst nematode .
 Seeds and seedlings – the use of healthy seeds and seedlings
have a material effect on subsequent overall status of cultivated
plants.
 Green manure, line protection cultures and increased biological
activity of the soil supporting the development of natural antagonists
of diseases and pests.

Nutrition of plants - plants with a balanced diet are more resistant to pathogens.
Moderate (ie limited) fertilization with nitrogen is essential. The plants in these cases have a
more compact and more rigid tissue. Plants fertilized with nitrogen are more susceptible to
attack - especially by some fungal diseases and pests.
 In organic farming, balanced nutrition is provided primarily through fertilization with
manure and green fertilization. The basic principle of organic farming, which positively
affects the sustenance of the good health status of plants is: "Do not fertilize the plants,
but the soil, which then harmoniously feeds the plants."

5.3. Control methods applied against
pests (diseases and insects) in
ecological (organic) vegetable
production
2017-1-BG01-KA202-036212

Organic products for plant protection of plant
origin / bioinsecticides / authorized under
organic farming
NIMAZAL T / C - Organic insecticide. Active material: Azadirachtin
 Effects: System bioinsecticides, penetrating. The action of the product is
expressed in the sterilization and reduction of the life activity of the adult insects.
The effect is expressed in adult distortion in the process of maturation of the eggs
of females after exposure to the product within the body. Larvae in the product
blocks the release within the body of the hormone ektizon, which distorts their
development, stop moulting and passage of another age larvae. After treatment
the effect is manifested by stopping the feeding , a few hours after exposure to
the product in the body of the mites .
In Bulgaria, Nimazal T/C is registered against two-spotted spider mite Tetranychus
urticae Koch in vegetables - 0.3%

Pyrethrum - Active substance: natural extract from Chrysantemum
cinerarifolium. Permitted use:
- Aphids on greenhouse crops - 0.05% (50 ml/ha)
- Trips, whiteflies and other insects in greenhouse culture, 0,05 % (50 ml/ha)
Effects: Pyrethrum is a biological insecticide with contact effect, and a very
fast initial effect, expressed in insect paralysis and blockage of the sodium
channels, thereby causing lethal effect on insects.
Application: Pyrethrum is used in glasshouse crops against aphids, thrips,
whiteflies and other insects. In organic farming the use and application of
permitted vehicles and plant protection products play a secondary role. In
most cases it is sufficient to take preventive measures in plant protection and
the preservation of healthy plants. Such measures are careful selection of
plant species and varieties, crop rotation and crop substitution and balanced
fertilization.

Biological control in organic farming
 Biological method in theory and practice is further elaborated in
two main areas:
 First, a broad study of the natural resources of beneficial
organisms determining their effectiveness, developing methods
for increasing their useful activity and
 Second, establish methods for the use of active beneficial
bioagents for close combat of certain pests by submitting them
to the infested areas.
 This includes creation of biological substances and mass rearing
of beneficial organisms in large amounts.

The main beneficial organisms that determine the
importance of biological control are two major groups:
 Micro-organisms - viruses, bacteria, fungi, protozoa
and nematodes. These diseases cause harmful insects,
mites and rodents which exhibit as antagonist agents of
plant diseases, certain diseases caused by weeds.
 Macro-organism predatory mites and spiders Arachnid
class and predatory bugs, beetles, hymenoptera ,
neuropterous and others. Class Insects . This group
includes frogs, reptiles, birds and mammals. All they eat
by destroying harmful organisms.

Netting and nonwoven fleece
Source: http://www.worthgardening.net/product_detail/non-
woven-fleece-tunnel-14688927470551135.html
Source: http://www.garden-netting.co.uk/
Nonwoven fleece and netting to protect against insects are especially suitable for the protection of cole crops against insects.
Nets prevent insects to insects (cabbage white, turnip fly) from invading the plants.
Nonwovens also improve the micro-climate (increase air humidity) to such am extent that they stop flea beetles from breeding.
However, if planning to use these materials, we must consider the cost of purchase and later disposal, and also higher labor input: the
material must be removed before each intervention, returned afterwards and anchored to resist wind.

References:
1. Borivoj Sarapatka, Jiri Urban et al. Organic agriculture, Prague, 2009.
2. М. Иванова, Теодора Илиева. 2013. Растителна защита. Мултимедийни презентации на лекционен курс за студенти от ВУАРР, специалност „Управление
на агробизнеса“, ОКС „Бакалавър“. ISBN 978-619-7048-30-8
3. Dimitrov D. & M. Ivanova. 2017. Trends in organic farming development in Bulgaria: applying circular economy principles for sustainable rural development.
Visegrad Journal of Bioeconomy and Sustainable Development. p. 10 – 16. https://www.degruyter.com/downloadpdf/j/vjbsd.2017.6.issue-1/vjbsd-2017-
0002/vjbsd-2017-0002.pdf
4. М. Иванова. 2017. Растителна защита. Учебник за дистанционно обучение.
Internet resources:
 http://ec.europa.eu/agriculture/organic/
 http://www.ifoam.org/en/organic-landmarks/principles-organic-agriculture
 http://www.fibl.org/en/homepage.html
 http://www.infonet-biovision.org/res/res/files/488.OrgFarm.pdf
 http://www.geneticliteracyproject.org/2014/03/25/organic-farmer-call-to-action-we-can-work-with-gmo-farmers-to-feed-
the-world/
 https://www.youtube.com/watch?v=q3ciISvqpTo
 https://www.youtube.com/watch?v=EXZUpzwOOZ8
 http://onlinebooks.library.upenn.edu/webbin/book/browse?type=lcsubc&key=Organic%20farming%20--%20Bibliography&c=x
 http://www.donlotter.net/lotter_organicag.pdf

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