FALL ARMY WORM IN MAIZE- A SERIOUS PEST
Fall Armyworm (Spodoptera frugiperda) causing crop damage to larger extent in maize in India. Recently it is reported in some districts of Karnataka. It is native of America and in 2016 it was serious pest in South African Countries on maize crop. Previous year this cut worm also affected the finger millet crop in some districts of Karnataka.
Infestations usually first develop in fields of small grains or in other grass cover crops. In conventional tillage systems, partially- grown larvae can migrate into corn fields from grassy waterways, damage is usually first noticeable around the field margins adjacent to these areas. The name armyworm derives from its behavior of migrating in large numbers into fields similar to invading armies. In no-till or reduced tillage systems, infestation may cover the entire field. In these systems, eggs may be laid on grasses within the field prior to planting and herbicides may force armyworms to feed on corn as the weeds or cover crop dies.
Cool, wet, spring weather usually favors armyworm development. The full-grown 1-1/2 inch armyworm has a greenish brown body with a thin stripe down the center and two orange stripes along each side. The head is brown with dark honeycombed markings. Eggs are small, greenish-white, globular, and laid in clusters of 25 or more on the leaves of grasses. The adult moth is tan with a tiny white spot in the center of the forewings. The moth has a wingspan of about 1-3/4 inches.
Armyworms usually feed at night and damage corn by chewing leaves. They prefer to feed on the succulent leaves in the whorl first. Feeding is usually confined to leaf margins, but occasionally they may strip the entire plant leaving only the midrib of the leaves. During the day, armyworms are found in the soil or underneath ground cover. Ragged leaf feeding in the spring and early summer is evidence of armyworm feeding. Corn can usually recover from light to moderate feeding by armyworm without significant yield loss. However, severe damage, particularly if the growing bud is injured, can cause significant loss in yield.
Following chemicals may be used to kill the pest. Spraying in the evening will be effective since they come out to feed in the night times.
Coragen 0.33 mL/L OR Rilon 0.5 gm/L + Neemark 1 % 1 mL/L
The army worm will be dwelling in the soil and will be coming out to feed the baiting technique may be an effective method to kill them. As the bait has attractant jaggery the larvae gets attracted to jaggery, feed on the bait mixture and will be killed avoiding them to feed on the corn. Bait mixture must be evenly broadcasted evenly all over the maize plot.
The process of baiting can be a mixture of 3 components,
- Poison (Insecticide): 2. Carrier or base (Rice bran), and Attractant (Jaggery) at ratio of 1:10:1. Mix all the items with given ratio to prepare the bait mixture.
The poison may a stomach poison insecticide can be used like Malathion or Phoskill
K Sanjeeva Reddy,
Senior Agronomist, BigHaat
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