Pest of onion

Pest of Onion, Thrips tabaci commonly known as onion thrips. It is a severe pest where both nymphs and adults suck the growing foliage of onion plant due to which decline the growth of the plant.

1. Dr. ArunB. Sawarkar
BP Arts, SMA Science & KKC Commerce College,
Chalisgaon, Dist-Jalgaon(MS)
2. Pest of Onion
Agriculture Pest
E-content developed by Dr. ArunSawarkar

2. Today’s discussion
a)About Onion plant
b)Pest of onion
c)About Onion thrips
Systematic position,
Marks of identification,
Life cycle,
Nature of damage and
Control measures

3. a) About Onion (Aliumcepa)
Onion is extremely important vegetable crop due to their nutritional properties and highest
foreign exchange earner among the fruits and vegetables.
In fact, the medicinal properties of onions have been recognized since ancient times, when they
were used to treat health problems like headaches, heart disease and mouth sores.
Onions are low in calories yet high in nutrients, including vitamins C and B along with
potassium.
A nutrient involved in regulating immune health, tissue repair and iron absorption, metabolism,
red blood cell production and nerve function.
Onions contain antioxidants and compounds that fight inflammation, decrease triglycerides and
reduce cholesterollevels ultimately lower heart disease risk. It lower risk of certain cancers,
including stomach and colorectal.
Eating onions may help control blood sugar, which is especially significant for people with
diabetes.

4. India is the second largest onion growing country in the world next to China. But in case
of productivity, India is very low as compare to China and other countries as Egypt,
Netherlands and Iran.
Indian onions are famous for their pungency and are available round the year. Itisthe
second most importantcommercialcropsoftheIndiawhich is next to Potato.Maximum
onion production takes place in Maharashtra followed by Karnataka, Gujarat, Bihar,
Madhya Pradesh and Andhra Pradesh.
Onion is a most important culinary commodity growth in India. Full yield potential of the
crop is not realized due to number of limitations. Among them pest and diseases are the
major constraints in onion production.

5. Thripstabaci(Onion thrips) (Thysanoptera: Thripidae)
Delia antiqua(Onion maggot or onion fly)(Diptera: Anthomyiidae)
Rhizoglyphusrobini(Bulb mite) (Acaridae: Sarcoptiformes)
Aceriatulipae(Eriophydmite)(Eriophyidae: Prostigmata)
Tetranychuscinnabarinus(Red spider mite)(Tetranychidae: Trombidiformes)
b) Pest of Onion

6. Onionthrips,Thripstabaciisapestincommerciallyproducedonionand
causessignificantyieldlossglobally.Thepeststatusofonionthripscanbe
attributedtoitspolyphagousnature,highreproductiverate,shortgeneration
time,highsurvivalofcryptic(nonfeedingprepupaandpupa)instars,abilityto
reproducewithoutmating(parthenogenesis),abilitytotransmitplant
pathogensanddevelopmentofresistancetoinsecticides.
Extensivefeedingbyonionthripsnotonlyresultsinplantstuntingand
reducedbulbweight,butitalsoinfluencesonionplantstovariousfungaland
bacterialpathogensthatultimatelyresultincompletecropfailure.

7. a) Systematic Position:
Class: Insecta
Order: Thysanoptera
Family: Thripidae
Genus: Thrips
Species: tabaci
Thripstabaci(Onion thrips)
b) Host plants
Onion, garlic, cotton, cabbage, cauliflower, potato,
tobacco, tomato, cucumber, brinjal, tea, pear, pine apple,
chillies, tomato, radish, grapes etc.
https://vegento.russell.wisc.edu/
pests/onion-thrips/

8. c) Marks of Identification
Nymphs:
It is white to pale yellow, elongate, slender body and lacks wings.
Nymphs resemble the adults in shape and colourbut are wingless
and slightly smaller.
Adult:
It is slender and yellowish brown in colour.
The forewings and hindwings are fringed and pale in color.
Mouthparts are piercing-sucking type.
Males are wingless and females have long narrow fringed wings.

9. d) Life cycle
A female can lay about 50-60 kidney-shaped eggs singly in slits
made in leaf tissue.
After the incubation period, small yellowish nymphs hatches.
Nymphs pass through four stages and are full-fed in 4-6 days.
After the nymphalperiod, they moves to the ground for pupation.
The pre-pupal and pupal stages last 1-2 and 2-4 days,
respectively.
Several generations are completed in a year.
(15-21)E N(4)
A
4
Days
4-6
Days
P
4-9
Days

10. e) Nature of damage
The damage is caused by both the nymph and the adult.
They lacerate the onion leaf tissue and suck the sap from the leaves.
Leaves of attacked plants turn silvery white, curl, wrinkle and gradually dry from tip
downwards.
The plants do not form bulbs nor do the flowers set seed.
Leaf tip discoloration and drying is the main symptom.


11. https://academic.oup.com/jipm/article/6/1/6/2936974

12. f) Control measures
i) Cultural methods
1.Use resistant/tolerant varieties.
2.Destruction of infested plants and crop residue after harvest.
3.Avoid planting of garlic or other alternate host such as cabbage, cotton, tomato,
cucumber, melons, pumpkins near the onion crop.
4.Use of reflective plastic silver colourand aluminiumpainted black mulches repel
the thrips(seed crop).
5.Use of sprinkler irrigation reduces thripspopulation considerably compared to drip
and surface irrigation.
ii) Chemical methods
1.Applicationof0.3%monocrotophos,0.03%dimethoate,0.02%diazinonor0.1%DDTare
effectiveincontrollingthepests.
2.FumigationbyusingCelphos(aluminiumphosphidetablets.

13. 1.Application of Aelothripssp., green lacewing larvae, coccinellidsadults are effective to
control the pest.
2.Ceranisusmenesparasitized onion thrips.
3.Entomopathogenicnematodes, Steinernemasp., Heterorhabditisbacteriophoraare effective
for control of onion thrips.
4.Entomopathogenicfungi, Beauveriabassianaand Metarhiziumanisopliaewere successful in
reducing onion thripspopulations and increasing onion yield.
iii) Biological methods

14. ModernEntomologybyDBTembhare,HimalayaPublishingHouse,Mumbai.
ATextbookofAppliedEntomology(Vol.II)byKPSrivastava,KalyaniPublishers,Ludhiana.
AgriculturalpestsofIndiaandSouth-EastAsiabyASAtwal,KalyaniPublishers,Ludhiana.
EntomologyandPestManagement,LarryP.Pedigo,PrenticeHall.
TextBookofAgricultureEntomology,AlfordV.David,BlackwellScience.
OnionThrips(Thysanoptera:Thripidae)Biology,Ecology,andManagement inOnion
ProductionSystems.HKGill,HarshGarg,AKGill,JLGillett-Kaufman,BANault,Journalof
IntegratedPestManagement.(2015)6(1):6.
https://vikaspedia.in/agriculture/crop-production/integrated-pest-managment/ipm-for-
vegetables/ipm-strategies-for-onion/crop-stage-wise-ipm
http://cues.cfans.umn.edu/old/inter/inmine/Thripk.html
http://www.agri.huji.ac.il/mepests/pest/Thrips_tabaci/#:~:text=Females%20lay%20about%2010
%2D20,period%20of%2015%2D%2030%20days.
Acknowledgment

15. E-content developed by Dr. ArunSawarkar
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