Fall Army Worm (Spodoptera frugiperda) and its Management Strategies

Dr Mukesh Babu


Central Integrated Pest Management Centre, Dimapur


Fall Army Worm (Spodoptera frugiperda) is a species in the order of Lepidoptera. It is widely distributed in Eastern and Central of North America and South America. In 2016 it was reported in Africa and spread to 28 countries. In Kharif, 2018 it was noticed on Maize crops in the state of Karnataka. Thereafter, its presence has been reported in from the state of Telangana, Andhra Pradesh, Tamil Nadu, Maharashtra, Chhattisgarh, Odisha, Gujarat, Madhya Pradesh, Rajasthan, Bihar and West Bengal, Mizoram, Assam, Manipur and Nagaland.


The Fall Army Worm is an exotic and invasive pest. It is a voracious feeder damaging economically important cultivated crops such as maize, wheat, potato, soya bean, cowpea, peanuts, sorghum, rice, sugarcane, vegetables, and cotton etc., which can feed on 80 different crops. The adult moths are capable of flying long distance and can fly 100 km in one night. 


Management Strategies of Fall Army Worm (Spodoptera frugiperda) on Maize Monitoring: 


Installation of pheromone traps @ 5 per acre in the current and potential area of spread in crop season and off-season.


Scouting: 


Start scouting as soon as maize seedling emerge
1.     At seedling to early whorl stage (3-4 weeks after emergence)- action can be taken if 5% plants are damaged.


2.    At mid whorl to late whorl stage (5-7 weeks after emergence)- action can be taken if 10% whorls are freshly damaged in mid whorl stage and 20% whorl damage in late whorl stage.


3.    At tassseling and post tasseling (silking stage) - do not spray insecticides (no insecticide application). But 10% ear damage needs action. 


Cultural Measures:
1.    Deep ploughing is recommended before sowing. This will expose FAW pupae to predators.


2.    Timely and uniform sowing over a large area is advised. Avoid staggered sowings.


3.    Intercropping of maize with suitable pulse crops of particular region. (eg. Maize + pigeon pea/black gram/green gram).


4.    Erection of bird perches @10/acre during early stage of the crop (up to 30 days).


5.    Sowing of 3-4 rows of trap crops (eg. Napier) around maize field and spray with 5% NSKE or Azadirachtin 1500 ppm as soon as the trap crop shows symptom of  FAW damage.


6.    Clean Cultivation and balanced use of fertilizers. 


7.    Cultivation of maize hybrids with tight husk cover will reduce ear damage by FAW.


Mechanical  Measures:
1.    Hand picking and destruction of egg masses and neonate larvae in mass by crushing or immersing in kerosene water.


2.    Application of dry sand in to the whorl of affected maize plants soon after observation of FAW incidence in the field.


3.    Application of Sand +Lime in 9:1 ratio in whorls in first thirty days of sowing.


4.    Mass trapping of male moths using pheromone traps @ 15/acre.
Bio-Control  Measures:


1.    In situ protection of natural enemies by habitat management: Increase the plant diversity by intercropping with pulses and ornamental flowering plants which help in build-up of natural enemies.


2.    Augmentative release of Trichogramma pretiosum or Telenomus remus @50,000 per acre at weekly intervals or based on trap catch of 3 moths/trap.


3.    Bio pesticides: If infestation level is at 5 % damage in seedling to early whorl stage and 10% ear damage, then use following entomopathogenic fungi and bacteria.

table


*    Bacillus thuringiensis v. kurstaki formulations @ 2g/litre or 400 g/acre.


*    NPV


*    EPN


Chemical Control  Measures:
1.    Seed treatment: Cyantraniliprole 19.8%+Thiamethoxam 19.8 % FS @ 6 ml/kg of seed will be effective for 15-20 days.


2.    First Window (seedling to early whorl stage): To control FAW larvae at 5%  damage to reduce hatchability of freshly laid eggs, spray 5% NSKE/Azadirachtin 1500 ppm  @5ml/litre of water.


3.    Second Window (mid whorl to late whorl stage): To manage 2nd and 3rd instars larvae having more than 10 % foliar damage the following chemical may be used upto early tasseling stage: Spinetoram 11.7 % SC OR Thiamethoxam 12.6% + lambda cyhalothrin 9.5% ZC OR Chlorantraniliprole 18.5% SC.


4. Poison baiting: Poison baiting is recommended for late instar larvae of second window. Keep the mixture of 10 kg rice bran + 2 kg jaggery with 2-3 litres of water for 24 hours to ferment. Add 100 g Thiodicarb just half an hour before application in the field. The bait should be applied into the whorl of the plants.


5.    Third Window (8 weeks after emergence to tasseling and post tasseling): Insecticide management is not cost effective at this stage. Hand picking of the larvae is advisable.


All the sprayers should be directed towards whorl and either in the early hours of the day or in the evening time.

 

Capacity building and mass awareness: 

*    Application and timely plant protection measures to avoid spread of the insect from the abandoned crop.


*    Creation of awareness among important stake holders through trainings/group discussion.


*    Community based area-wide approach for implementing management strategies.