Diseases of marigold

1. PESTS OF MARIGOLD

2. Marigold
• The African Marigold (Tagetes erecta)
French Marigold (Tagetes patula)
In genus Tagetes there
are 33 species, but
commercially two species
T. erecta and
T. patula are grown in
our country and in
western countries
another species T.
tenuifolia is also grown.

3. 1. Bud caterpillars
Helicoverpa armigera and
Phycita sp.
Activity:
• Marigold is one of the preferred host of H.armigera
Nature of damage
H.armigera
• Eggs are laid singly on young buds.
• Hatched larvae bore into buds and growing flowers and feed on
developing flowers by damaging florets and petals
• On an average 4-5 larvae are seen per plant
Phycita sp.
• Larvae of Phycita sp. damage flowers by making groove on the
central receptacle and feed on ovaries and stamen filament
• Excreta on damaged flowers

4. Management
• Collection and destruction of infested buds and
flowers and matured larvae reduce further damage.
• spray HaNPV @250LE/ha
• Setting up of light traps to attract and kill the adults.
• Spray of NSKE @ 4.0 %
• Emergency spray of spinosad @ 0.4ml/L or indoxacarb
@ 0.6 to 0.7ml/L or flubendiamide @ 0.2 to 0.5ml/L or
coragen @ 0.3ml/L

5. 2. Aphids, Aphis gossypii
(Hemiptera:Aphididae)
Nature of damage
• Aphids mainly infest lower surface of flowers and
base of petals.
• Nymphs and adults suck the sap from the flowers
causing discolouration and withering.
• Infected plants become weak and unproductive.
• Aphids can cause a lot of damage to marigolds,
including stunted growth, mottled leaves,
lowered rates of growth and curled foliage.
• With infestation by aphids, marigolds will have
sticky secretions over their newer buds and
leaves.

6. Identification
• These are small insects green to bluish-grey or
black in colour.
• These usually occur in clusters and damage the
apical growing portion by sucking the plant sap.
Management
• The pest can be controlled by need based
spraying of crop with pymetrozine 50 WG @
0.6g/L or flonicamid 50 WG @ 0.3g/L.

7. 3. Red spider mite, Tetranychus urticae
(Acarina: Tetranychidae)
Activity: The mites become active during the flowering
period , August-September, November
Nature of damage:
• These are spinning creatures, red and brown in colour
• Colonies of mites are found on lower surface of leaves
which are covered by dirty webs
• Both nymphal and adult stage feed on plant sap
• Affected leaves discoloured
• The speckling, discoloration and dusty appearance of
the leaves easily identify the attack
• Attacked plants get stunted in growth, wilt and dry if
damage is severe

9. Management
• Cut and burn the severely infested plant parts
• Thoroughly spray water on plant for
dislodging the webs
• Spray miticide like dicofol @ 3 – 5ml/L or
spiromesifen @ 0.6 to 0.8ml/L or propargite
@ 1ml/L followed by a spray of pongamia oil
@1% is recommended for effective control.

10. 4. Leaf miner, Liriomyza spp.
(Diptera: Agromyziidae)
• The most important species are Liriomyza
trifolii and the pea leafminer (L. langei).
Identification
• Adult Liriomyza are small, active, black and
yellow flies.
• Larvae are yellow cylindrical maggots that
feed beneath the leaf surface.

12. Nature of damage:
• Adult female leaf miners puncture leaves and sometimes petals
to feed on exuding sap. These punctures eventually turn white,
giving foliage a stippled or speckled appearance.
• The most obvious evidence of leaf miners is the twisting trails
(or mines) the larvae leave as they feed beneath the leaf
surface.
• The mine becomes longer and wider as the larva grows.
• Mining usually has little impact on plant growth and rarely kills
plants.
• Unusually heavy damage can slow plant growth and may cause
infested leaves to drop.
Management:
• Remove and destroy severely mined leaves to reduce further
damage
• Spray NSKE 5% or chlorpyriphos @ 2ml/L or abamectin or
Fipronil @ 1.5ml/L.

13. 5. Thrips ,Thrips tabaci (Thysanoptera: Thripidae)
Damage symptom
 Thrips prefer to feed in rapidly growing tissue.
 Discoloured or distorted plant tissue is the clues
that thrips are present.
 Damaged leaves become papery and distorted.
 Infested terminals may discolour, rolled and drop
leaves prematurely.
 Petals may exhibit “colour break,” which is pale
tissue that was killed by thrips feeding before
buds opened.
Control measures
• Set up blue sticky trap 20 per acre
• The pest can be controlled by need based
spraying of crop with pymetrozine 50 WG @
0.6g/L or flonicamid 50 WG @ 0.3g/L.

14. 6. Mealy bug: Planococcus citri
(Hemiptera: Pseudococcidae)
Damage symptom:
• Mealy bugs are crowdly present
in young shoots, stem and leaves.
• Flattening and crinkled with dark
green leaves.
• It secrets honey like substances
because of that leaves are
converted into black sooty
mould.
• Apical parts of the shoots show
retarded growth.

15. 7. Leaf Hoppers, Amrasca biguttula biguttula
(Hemiptera: Cicadellidae)
Activity: cause considerable damage to the foliage of the
plant, particularly during rainy season.
Symptom of damage
• The symptom appears as rolling and curling of leaves along
with wilting of shoots.
• French marigold is more susceptible than African type.
• Infested marigold leaves become cupped; their edges roll in
toward the midrib and twist on their stalks.
• Branch tips and leaflets may wilt, which inhibits blooming.
• Leaves yellow and dry out, those that are exposed to bright
sunlight turning purplish first.
• Some common signs of infestation by leafhoppers are the
leaves becoming disfigured and discoloured in appearance.
• Some leafhoppers spread virus diseases such as aster
yellows.

16. Identification:
• Leafhoppers are strikingly colored, blunt-
profiled bugs, 1/4 to 1/3 inches long, wedge-
shaped, with wings held in a rooflike position
above their bodies.
• They're very active, moving sideways or
hopping suddenly when disturbed.

17. Management
1. Rogue out infested plants as soon as they
appear in the field and completely destroy them.
2. The pest can be controlled by need based
spraying of crop with pymetrozine 50 WG @
0.6g/L or flonicamid 50 WG @ 0.3g/L.

18. THANK YOU