IPM - Potato pests

POTATO
INTEGRATED PEST
MANAGEMENT

Potato tuber moth
 General :
1. The caterpillars of the potato tuber moth
(Phthorimeae operculella) can cause damage to
potato crops, in particular to the tubers, in
tropical and subtropical areas, both before
harvest and during storage. The amount of
damage varies with the cultivar.
2. It can also live on other members of the
Solanaceae.

 Symptoms :
1. The caterpillars first make mines in the leaves,
leaf veins and stems. These usually cause little
damage, unless large numbers of caterpillars
colonize an emergent crop .

Leaf damage by caterpillar of PTM the larva could be seen on the leaf

• Symptoms :
• If the caterpillars make mines in the tubers
• If the affected tubers are not stored
properly they will often rot.

Potato tuber moth damage on different
parts of potato plant
Potato leavesPotato stemPotato tubers

 Life cycle :
1. With in an optimum temperature range of 27-
35°C, the life cycle is completed in 20-25 days:
the eggs incubate for 3-4 days, the caterpillar
stage lasts about 7 days', the pupal stage 3-5 days,
and then the moth (3) is active for about 7 days
during which it lays 50-200 eggs.
2. At 18°C the cycle takes 50-60 days. Below 16°C
the eggs do not hatch though the caterpillars do
not die at a storage temperature of 4°C.

 Pest Description :
1. The 10-15 mm long caterpillars are grayish white
to yellow and have a dark brown head.
2. The moth, which has a silver body (about 10 mm
long) and grayish brown wings (wing span about
15 mm) is nocturnal and not easily seen.
3. The white/yellow eggs, with diameters of only 0.5
mm, are laid on the underside of the leaf, at the
foot of the stem and on the tubers, usually around
the eyes, but they may also be laid in other places
besides on plants.

Pupa & moth ( about 10 mm long )

Tuber damage damage by caterpillar of PTM the larva could be seen on the leaf

Prevention/control
 To prevent tuber injury, ensure adequate hilling
without cracks in the soil.
 Spray crops with insecticides to kill the moths
and caterpillars.
 Spray storage areas, too, if potatoes are to be
stored at temperatures above 10°C.

Fall Armyworm
(Lepidoptera, Noctuidae)
 A larva may be identified by the inverted “Y” on the front of its head
 Life cycle requires 30-35 days; feeds for 14-16 days through 6 larval instars
 >90% of the grass consumed is in the last two larval stages
 Damage: small larvae give grass a ‘lacy’ appearance which develops into a
brownish cast; large larvae frequently consume entire blades of grass
 Chemical control (Dimilin, Lannate or Sevin) is most effective when directed
toward larvae that are <1/2 inch in length

Potato stem borer
 General
1. The potato stem borer is the caterpillar of a
brownish-red owl moth (Hydroecia micacea) and
may be noticed on all soil types.
2. In addition to potatoes it causes feeding injury
in beet and maize.

 Symptoms :
1. Affected stems wilt because, as a consequence of
internal injuries caused by the caterpillar's feeding, the
transpiration stream is hampered or even inhibited.
2. When the stem is cut lengthwise the caterpillar may
be seen inside the stem .
3. After the caterpillar has left the stem the round
opening in the stem base, combined with the
hollowed-out stem containing (remains of) the
caterpillar's excrements, is unmistakable evidence for
the originator of the damage.

Full grown larva inside potato stem

 Life cycle
1. H. micacea overwinters as eggs which the moth deposits
in grassland and on succulent plants growing in rough
herbage along ditches and roads.
2. the flesh-coloured to reddish caterpillars appear at the
end of April and in May. They migrate to and invade
herbaceous plants, boring mines in stems in which they
feed and stay for virtually the rest of their lives as
caterpillars, becoming up to 4 cm long. At the end of
June/beginning of July the caterpillar eats a round
opening in the stem base, through which it leaves the
stem to pupate in the soil.
3. The pupal stage lasts about one month. The cycle ends
with the appearance of the moths in August, to lay
wintering eggs in September & October.

 Prevention/control :
1. In general damage caused to potatoes is
limited because usually only one or a few
stems per plant are affected of plants growing
along ditches or on the edges of fields.

1. The only preventive measure is to treat soil of
plots where there is believed to be a risk of
damage due to wireworms with an approved
soil-treatments agent before planting the
potatoes.
2. It is not possible to control wireworms in a
growing crops.

leaf miner ( Liriomyza sp. )
 Symptoms :
1. Before depositing her eggs, the female leaf miner
punctures several plant cells with her ovipositor and then
sucks up the cell contents leaving empty cells visible as
white dots in the leaves .
2. Female deposits her eggs through the hole, beneath the
leaf epidermis.
3. The larvae that hatch from these eggs mine through the
leaf .
4. The mines, which are a pale cream colour, often run
alongside or in the veins but, they may also run crisscross
across the leaf.
5. they can be seen mainly on the underside of the leaf. The
larvae pupate either on the leaf or in the soil.

 Life cycle :
1. Under favorable conditions the fly-egg-larva-pupa
cycle may be completed in a short time. At a
temperature of 18-19°C an egg will hatch, on average,
in two days. The larval stage lasts for five to six days,
the pupal stage for seven to eight days. This short
development time (15-17 days at 18-19°C) means that
a population can expand rapidly.
2. The insects can be spread by affected plant parts but
they also spread easily through the air by flying.
3. leaf miner can develop well on both cultivated and
wild plants.

Leaf miner punctures several plant cells
White dots on the leaf are group of cells
damage done female puncturing
Enlarged mines

 The main control method is chemical through
the use of Abamectin 1.8% EC, Ceromazine,
etc…

Cutworms
 General :
1. Cutworms are the larvae of various species of
noctuid moths (owlet moths), including Agrotis
segetum .
2. They cause injury to all kinds of crops: they
feed on the plants themselves, while the
wounds that they produce can serve as
infection courts for other damaging organisms,
such as the bacteria causing soft rot.

 Cutworms Life Cycle :
1. Cutworms ( Agrotis segetum ) are 3-5 cm long dirty grey
caterpillars. that rest rolled up in a distinctive C-shape
in a hole in the soil during the day and are active at
night
2. The eggs are laid on leaves. the young caterpillars first
feed on the leaves and then burrow into the soil after
their first molt.
3. In soil they feed on roots and tubers.
4. The caterpillars, which are fully grown in the autumn,
overwinter, pupate in the spring, and then develop
into moths.

Adult moth ( 4 cm ) Grey cutworms and tuber mines

 Symptoms & Importance:
 It is the most important insect in the Bekaa since
farmers cannot observe its damage on their yield
until harvest, especially when irrigation is
decreased at the end of the season. They feed on
the root and tubers, tunneling through them and
making them unmarketable.
 As to the control of these insects, it is mainly
chemical with the use of insecticides.
 Nevertheless, for more effective control of
cutworms, baits of grind wheat soaked with
Methamidophos or Diazinon are often used by
spreading under the plants.

Chafer Beetle
white grub complex

White Grubs
(Coleoptera, Scarabaeidae)

 Cockchafer Life Cycle :
1. The 3-6 cm long chafer grubs are white to
yellow/white and have a grown head and large
legs .
2. They are usually curved towards their
abdomen.
3. The larvae of cockchafers usually remain in
the soil for 3-5 years and they overwinter deep
underground.

Yellow- white chafer grubs with brown head ( 4 – cm long )

B. White Grub Monitoring Procedures:
 Materials and Equipment Needed :
 To monitor for white grub you will need a shovel and a
dark cloth about one yard square.
 Monitoring Procedures :
 When the soil warms up in the spring (> 45 o F at a
four inch depth), grubs move up and begin to feed on
the roots of grasses. In old sod fields, dig up a one
square foot area about four inches deep (root zone of
grasses) and place it on the dark cloth. Shake the soil
off the roots. Then break the sod apart and look for
grubs that are close to the surface. Shift through the
soil on the cloth. Count the total number of grubs per
one square foot area. Repeat the process in at least 9
more locations.

Wireworms
 General :
1. Wireworms are the yellow to yellowish-brown larvae
of certain species of click beetles.
2. Three of the large number of species of these beetles
are of agricultural importance: Agriotus lineatus, A.
obscurus and A. spectator.
3. In some years and some places they can cause a lot of
damage.
4. It is difficult to remove affected tubers when grading
because the holes made by the wireworms are small.
Severely affected stocks are not marketable

 Symptoms :
1. Wireworms bore numerous shallow holes, and
sometimes also mines, into tubers.
2. These holes and mines become filled with excrement,
which eventually turns dark brown. Sometimes tubers
still contain wireworms when they are lifted. stored
potatoes rarely contain them.
3. Wireworms may also bore into seed potatoes.
Sometimes underground parts of stems and stems of
young plants are also affected (hollowed out), but this
damage is usually of little importance.
4. Occasionally the feeding injury causes an uneven stand.
Rhizoctonia solani may cause small holes resembling the
injury caused by wireworms

 Life cycle :
1. The black to brownish black click beetles emerge from the
ground in the spring. A distinguishing feature of these beetles is
the clicking sound that they produce as they leap up when they
are placed on their backs.
2. The beetles lay their eggs preferably in slightly moist soil.
3. The larvae (wireworms) hatch from the eggs shortly after they
have been laid and the larval stage then lasts four to five years.
4. Up to the autumn of the first year the wire-worms feed on dead
organic remains and in that period they therefore cause no
damage to crops. They start to cause damage in the spring of
the second year. In the autumn the wireworms burrow deep
into the soil to emerge again in the spring and it is then and in
early summer that they cause most damage.
5. Cereals, maize, potatoes and beets are affected most. The
beetles show a preference for grassland and clover when laying
their eggs and so their larvae (wireworms) often cause damage
to potato crops grown in ploughed grassland or mulched clover.

Wireworm Monitoring Procedures:
 Materials and Equipment Needed :
 To monitor for wireworm you will need a shovel or trowel, large mesh netting
(about the size of a wedding veil), and some corn or small grain. The mesh
netting should be small enough to prevent the grain from passing through.
 Monitoring Procedures :
 Monitoring can be initiated when the soil temperature reaches 45oF at a soil depth of four
inches. At ten locations in the field dig a hole four to six inches deep and place
one small bag made of the mesh netting, containing the grain, into the hole .
 Tie the bag at the top with a rubber band or string. Bury the bag and leave it
for one to two weeks. Mark each location with a flag or other device that is
easy to relocate. After the one to two week period is over, return to the bags
and dig them up. Open the bags and count the number of wireworms in each
bag.
 bout the monitoring procedure - This method is based on the wireworms'
attraction to carbon dioxide. As grain absorbs water from the air and soil, it
begins to respire giving off carbon dioxide. Wireworms in the soil move
toward a carbon dioxide source to locate roots and seeds. The seeds in the bag
serve as a carbon dioxide source. If wireworm populations are in the field,
they will be attracted to the bags of germinating seed.

 Leatherjackets Life Cycle :
1. They are legless, grey, 2-4 cm long larvae which
live near the surface of the soil and feed mainly
on underground plant parts.
2. Crane flies (Tipula species) lay their eggs in the
soil.
3. The larvae, which cause much damage pupate
in soil.

 Crane fly ( Tipula paludosa ) 2- cm long

1. Treat the soil of plots where there is thought to be a
risk of damage due to cutworms, chafer grubs and
leatherjackets with an approved pesticide before
planting the seed potatoes.
2. Leatherjackets can be controlled in the autumn or the
spring shortly before ploughing up grassland or
mulching perennial grass stubble, a manure crop or
Lucerne.
3. The pests cannot be controlled in a growing crop.

Mole Crickets
(Orthoptera, Gryllotalpidae)
 1-2 generations per year
 Presence may be detected by their tunneling in warm, moist soil
 Damage: Root feeding reduces stands; tunneling may dislodge seedlings
 Use of baits containing toxicant may temporarily reduce populations;
introduction of pathogenic nematode may provide some suppression

Leafhoppers
 Leafhoppers affecting potatoes are about 3 mm long and
cigar-shaped. Empoasca decipiens and Empoasca flavescens are
both pale green, whereas the chrysanthemum leafhopper,
Eupterix atra-punctuata is speckled yellow/black.
 In hot summers these insects may cause considerable
sucking damage. The symptoms of such injury are tiny
light dots, smaller than 1 mm, on the upper side of the
leaf, scattered across the mesophyll in small clusters .They
indicate the presence of large numbers of leaf-hoppers on
the foliage, which fly up when the plants are touched.
 Young leafhoppers and exuviae (old cuticles shed in
molting) can often be seen on the underside of the leaflets.
In severe cases browning and dying back of the leaves
occurs.
 Several leafhopper species are well-known vectors of
mycoplasmas.

 White spot on surface  Leaf hopper & exuviae
 Slight injury of leafhopper  Leaflets severely injured

Mycoplasma like disease
( Purple top )
Mycoplasma disease marked rolled leaflets & red colored top leaves

Different potato varieties affected by stolbur

Hair sprouts , as a result of infection by a mycoplasma

Peach Aphid Potato AphidBuckthorn potato aphid

Buckthorn wingless aphid Wingless potato – peach aphid

Potato Aphid
 Potato aphids are more slender than green peach
aphids and have longer legs.
 They are also more active than the green peach
aphid. Potato aphids build up on the terminal
growth of potatoes.
 These aphids cause less of a problem than green
peach aphids because they are more easily
controlled and aren’t as efficient a vector of
virus diseases as the green peach aphid.

Aphids
 General :
1. Aphids constitute a major threat to the cultivation of seed
potatoes because they can transmit viruses, such as the potato
viruses A, Y, S and M, from one plant to another in a most
efficient manner. As the quality of seed potatoes is largely
dependent on the level of virus infection it is understandable
that much attention is paid to the behavior of aphids.
2. In addition to the damage resulting from the transmission of
viruses, aphids can also cause damage directly, in the form of
the disease known as 'False top roll' and by injury due to
feeding damage.

Aphids
 Macrosiphum euphorbiae : Potato aphid.
 Myzus persicae : Green Peach aphid.
 Aulacorthum solani : Glasshouse-potato aphid .
 Aphis nasturtii : Buckthorn potato aphid.
 Myzus ascalonicus : Shallot aphid.
 Many other aphid species visit potato plots and puncture
plants in their search for food. Once they have punctured a
plant infected with a virus, some species can transmit that
virus to other plants in the crop.
 Mixed population of young and old aphids can increase
five-fold within one week. However, in the presence of
many enemies, for example ladybirds, hover flies, and
lacewings, a population may also decrease tend-fold within
one week.

 Symptoms :
1. Aphids are found mainly on the undersides of the leaves . The
saliva that is introduced into the leaves by the sucking aphids
can cause deformation, twisting to contraction of the leaves.
2. Aphids also secrete honeydew, which covers the leaves as a
shiny mass, making them sticky. Black fungi may develop on
the honey-dew, which give the crop a dirty, grey appearance.
3. If the tops of the stems contain many aphids, they too may
become deformed.
4. In addition, the 'Rosa' strain of the potato aphid can cause the
phenomenon known as 'false top roll'.

 Prevention/control : Seed potatoes:
1. Young plants are particularly susceptible to infection with a
virus and seed potato plots must therefore be kept free of
aphids where possible, in particular early in the season.
2. It is best to cultivate seed potatoes in areas where only a few
aphids occur.
3. Measures aimed to accelerate the development of a crop, such
as pre-sprouting, are also important.
4. Removing plants showing sign of infection with a virus
5. Various pesticides are available for aphid control. If natural
enemies are present, it is preferable to use selective pesticides
which do not kill them.

 Prevention/control : Table potatoes :
1. Control of aphids in table potatoes is necessary only if there is
a risk of yield losses.
2. To prevent the re-occurrence of top roll in areas where it has
caused damage in the past.
3. Control will also be necessary if there are many plants with tops
deformed due to aphids or if black fungi develop on honey-
dew on the foliage because these fungus may reduce the
effective area of green leaf and so slow the rate of
photosynthesis and hence the plant's production.
4. If a crop that is not intended for the production of seed
potatoes is colonized by aphids, but shows no deformed tops or
black fungi, and if control of false top roll is no longer
required, aphid control will be worthwhile only if there are on
average more than 50 aphids per fully grown composite leaf.

Transmitted potato virus
Yellow spots
Necrosis in tuber
 Potato aucuba mosaic virus transmitted by Myzus persicae in non-
persistent manner

Potato Leaf Roll Virus
PLRV is spread only by aphids and these transmit it in the persistent manner.
The peach-potato aphid, Myzus persicae, is the most efficient vector
Primary infection with PLRV Secondary infection with PLRV

Plant secondary infected with leaf roll with a pale , rigid top

Potato Virus Y
 Strains of potato virus Y can be transmitted in the field
in a non-persistent manner by a wide range of aphid
species.
 The most efficient vector is the peach-potato aphid
(Myzus persicae).
 Others are the buckthorn-potato aphid (Aphis nasturtii),
the common potato aphid (Macro-siphum euphorbiae), the
brown aphid (Myzus certus), the leaf curling plum aphid
(Brachy-cauclus helichrysi) and a number of cereal aphids.

Crinkling
Stipple Streak
Secondary infection with PVY

Potato Virus A
 Potato virus A is transmitted in the field in the
non-persistent manner by seven aphid species,
including the peach-potato aphid (Myzus persicae)
and the common potato aphid (Macrosiphum
euphorbiae).

PVA
infected potato plant infected with PVA

Potato Virus M
( Potato Leaf Rolling MOSAIC )
 Potato virus M can be transmitted by contact,
but in the field it is usually transmitted by aphids
in the non-persistent manner. Peach-potato
aphids (Myzus persicae) and buckthorn-potato
aphids (Aphis nasturtii) are the most important
vectors.

Potato Virus S
Potato virus S is transmitted in the field by contact between infected and healthy
plants. Some strains are transmitted by aphids.
Slightly limp and some what bronzed leaves

Bug on plant leaf ( 7 mm long )

 General
1. The plant bugs that cause serious injury to the foliage
of potato plants are piercing/sucking insects
belonging to the species Lygus babulinus.
2. The damage is almost always localized along hedges
and woodland boundaries.
3. Even the slightest leaf injury due to bugs interferes
with roughing practices which are a prerequisite to
produce virus-free crops.
Bugs

 Symptoms :
1. The bugs affect mainly recently formed young plant
parts. With their stylets they make invisible small
wounds in young leaves, around which the tissue turns
yellow to brown and dies shortly after. This results in
small holes, which at first sight slightly resemble the
symptoms caused by leaf feeding insects .
2. Frequently there is such an abundance of little holes
that the stem tops look slightly burned and often are
severely deformed.
3. In extreme cases little more than the veins and a few
remnants of the leaflets remain at the top of the plant.

 Life cycle :
1. The adult bugs found on potato plants are green to brown and
about 7 mm long . They undergo incomplete metamorphosis and
can be recognized by their flattened bodies.
2. When the bugs are resting they fold their wings flat over their bodies
and a conspicuous triangular part of the central thoracic segment
remains visible between the wing bases, the so-called scutellum.
3. Although the bugs are very motile, they are not readily seen because
they usually move around on the underside of the leaves. Indeed,
their presence is often not noticed until the plants start to show the
typical evidence of the injury they cause. When disturbed they
usually drop from the leaves or fly a short distance.
4. Several generations may develop within one growing season. The
bugs do not survive cold weather and they overwinter as eggs, which
are laid in the bark of woody plants.
5. The juveniles are wingless and travel only short distances. This
explains why the damage is almost always localized along the edges
of ditches, woodlands and hedges.

Slugs
 Symptoms
 Slug feeds on tuber causing holes and cavities of
varying sizes in tubers . sometimes leaving only the skin
of the tuber.
 Seed potatoes have also been known to have been
hollowed out entirely within a few weeks after they
were planted .
 Slime and feces on leaves and tubers show the presence
of slugs.

1. Try to minimize the number of places where
slugs can hide through effective weed control
and by ensuring the finest possible soil structure.
2. very difficult to control with pellet baits
containing metaldehyde or methiocarb.

PEST MANAGEMENT of Potato
IN LEBANON

IPM - Potato pests

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