Pests of Onion and Garlic_Bionomics_IPM_Dr.UPR.pdf

Onion thrips, Thrips tabaci, Thripidae, Thysanoptera

Symptoms of damage
Small white silvery patches are seen all over the leaves
In severe infestation, leaves dry from tip to downward

Management
Clean cultivation, regular hoeing
Flooding of infested field will check the thrips population.
Spray insecticides Dimethoate @ 0.06% or Profenofos @ 0.05%

1. Pests of Onion and
Garlic
By
Dr. U. Pirithiraj, P.hD.
Assistant Professor (Entomology)
JSACAT
Affiliated to Tamil Nadu Agricultural University

2. Onion thrips, Thrips tabaci, Thripidae, Thysanoptera1
Dr. U. Pirithiraj, P.hD. (Entomology)
Distribution:Southern Asia with records mostly from India and Bangladesh
Symptomsof damage
Small white silvery patches are seen all over the leaves
In severe infestation, leaves dry from tip to downward
Management
Clean cultivation, regular hoeing
Flooding of infested field will check the thrips population.
Spray insecticides Dimethoate@ 0.06% or Profenofos@ 0.05%
Laid only in the tender leaf
Colourvaries from pale
yellow to grey

3. Onion fly, Delia antiqua, Anthomyiidae, Diptera
2
Dr. U. Pirithiraj, P.hD. (Entomology)
Distribution.Widely distributed in France, Germany, Canada, USA, Japan, erstwhile USSR and
England. This pest also attacks onions in northern India.
Damage symptoms
Themaggotsboreintothebulbs,causing
theplantstobecomeflabbyandyellowish.
Itcauseswitheringinthefieldandrotting
instorage.Damageleadstotheinvasion
ofBacilluscarolovoruswhichcausessoft
rotofonion

4. White eggs near base of the
plant, in cracks in the soil
Maggots are small, white
and about 8 mm. in length
Flies are slender,
greyish, large-winged
Pupate in the soil
Management
GrowAllium fistulosumas it is more tolerant thanA. cepa.
Apply 10 kg of Carbaryl4G or PhoratelOGto the soil followed
by light irrigation.
Spray MethyDemeton25 EC or Dimethaote30 EC 1.0 L in 500 –
750 L of water per ha.
Dr. U. Pirithiraj, P.hD. (Entomology)

5. Earwig, Euborelliaannulipes, Forficulidae,
Dermaptera
3
Dr. U. Pirithiraj, P.hD. (Entomology)
Damagesymptoms
Nymphsboreintothebulbandmake
cavitieswhichleadtowitheringofplants.
Bionomics
Adultisbrowntoblackwithforcepslike
caudalcerci.Adultfemalelays21-139eggs,
eggperiod14days.Nymphswhiteinthe
earlystageturnbrowninthelaterstage,
nymphalperiod50-54days.
Parental care

6. Tobacocaterpillar, Spodopteralitura, Noctuidae,
Lepidoptera
4
Dr. U. Pirithiraj, P.hD. (Entomology)
Nature of damage
Early instar larva remain gregarious
and cause skeletonization.
Later instar cause defoliation
Symptom of damage
Skeletonization, defoliation
The countries with the most widespread population of S. liturainclude but are not limited toChina,
Indonesia, India, Japan, and Malaysia

7. Yellow in colour, laid in mass
and covered with hairs.
Pale greenish with dark markings; gregarious in
the early stages
Brown colour,
obtectpupa
Dr. U. Pirithiraj, P.hD. (Entomology)

8. Moth with wavy white markings on a brown forewing. Hindwings
white with a brown patch along the margin
Dr. U. Pirithiraj, P.hD. (Entomology)

9. Management
Hand pick and destroy the caterpillar
Summer ploughing to expose to the pupae
Use light trap
Apply Bacillus thuringenesis
Field release of egg parasitoid such asTelenomus
spodopteraeand Telenomusremus
Field release of entomopathogenic fungusNomuraea
rileyi
Dr. U. Pirithiraj, P.hD. (Entomology)

10. Black cut worm, Agrotisipsilon, Noctuidae,
Lepidoptera
5
Dr. U. Pirithiraj, P.hD. (Entomology)
Symptom of damage
Cutting of tender stem and defoliation.
Nature of damage
Larva defoliates the crop.
SouthernCanada, United States,Mexico, Central and South America,Australia,New Zealand, thePacific
Rim,North Africa, Europe, and Asia

11. Creamy white, dome-shaped
eggs, laid singly on lower
surface of the leaves
Dark brown pupae are found in earthen cells lying
underground
Newly emerged young larva is yellow in colour.
The full-grown larva is dark or dark brown/black
with a plump and greasy body.
Dr. U. Pirithiraj, P.hD. (Entomology)

12. Dark with some grayish patches on the back and
dark streaks on the forewings.
Dr. U. Pirithiraj, P.hD. (Entomology)

13. Management
Flood the infested fields
Handpick and destroy the larvae in morning and evening hours on cracks and
crevices in the field
Plough the soil during summer months to exposelarvae and pupae to avian
predators
Set uplight trap @1/ha
Pheromone traps @12/ha to attract male moths
Spray insecticides like Chlorpyriphos20 EC @1 lit/ha or neem oil @ 3%
Dr. U. Pirithiraj, P.hD. (Entomology)