Important Pests of Field Crops

In this article we have covered important pests of field crops their symptoms, damaging stages, and their management.

Important Pests of Rice

1- Paddy Stem Borer

The caterpiller of paddy stem borer (Tryporyza incertulas) borer into the stem near the root, causing “dead heart” or wilting of central shoots, which easily comes out when pulled. At flowering the ear dries up without development of grain. It can be controlled by spraying 250 ml Phosphamidon or 500 ml Monocro- tophos 36 SL in 1,000 litres water three times at 30, 50, 75 days after transplanting.

2-Rice gandhi bug

Rice gandhi bug (Leptocorisa acuta) emits a pungent smell in the field. The adults and nymphs suck juice from developing grains at milk stage and make the grain pungent. It can be controlled by the application of methyl parathion 2% powder @ 25 kg/ha; spraying Malathion 25 EC @ 0.1 and use of light traps for collecting adults.

3-Rice hispa

The larvae and adults of rice hispa (Dicladispa armigera) feed on green parts; the damage starts in nurseries and spreads in field. The damage is caused by larvae; the adults feed on green matter and produce parallel whitish streaks on the leaves. It can be controlled by roguing, flooding and spraying methyl parathion @ 0.02%.

4-Paddy gall fly

Paddy gall fly (Orseolia oryzae) attacks tillers, which become hollow and deformed. There is a swelling or gall formation on the basal portion. Its growth is stopped and the central leaf ultimately turns into a hollow outgrowth, giving a shining silvery colour called silver shoot. The infested ear does not bear grain. It can be controlled by removal of alternate hosts and spraying Quinalphos 25 EC @500 ml/ha.

Pest of Maize

Grasshopper

Maize grasshopper (Hierog-lyphus nigrorepletus) damages plants by feeding on leaves and shoots. Under severe attack they completely defoliate the plant, leaving only the mid rib. Greatest damage by this pest occurs during August and September. It can be controlled by application of 2% methyl parathion dust or Malathion 50 EC @1 litre/ha. It also feeds on rice, sorghum, pearlmillet, sugarcane and other millets, arhar etc.

2-Stem borer

The caterpillar of maize stem borer (Chilo partellus) bores into the stem and feeds gregariously, sometimes making it hollow. The attacked plant in early stage shows dead heart, whose base smells offensively. It can be controlled by summer ploughing and spraying Endosulfan 35 EC @0.05%. It also attacks sorghum and pearlmillet.

Important Pests of Sorghum

1-Sorghum shoot fly

The sorghum shoot fly (Atherigona soccata) attacks at six leaf stages of crop. Maggots feed on main shoot and growing point, and by the time they pupate the plant is almost dead. The young plants show typical dead heart symptoms. It can be controlled by the application of Carbofuran 3% G or Chlorpyriphos 5% G@3-5 kg/ha after 30 days of germination.

2-Sorghum shoot bug

Both adults and nymphs of sorghum shoot bug (Peregrinus maidis) feed gregariously on leaf whorl, leaf sheath and leaves. They suck the cell sap; consequently the leaves turn yellow and growth is retarded. It can be controlled by application of methyl parathion dust 2% @25 kg/ha or spraying Malathion 50 EC @0.1%.

3-Red hairy caterpillar

Red hairy caterpillar (Amsaca moorei) feeds on leaves and tender stems. It makes holes in the leaves. It can be controlled by use of light traps, application of methyl parathion 2% 25 kg/ha dust and spraying methyl parathion @0.02%.

Important Pests of Wheat

1-Termites

Termites (Odentotermes obesus) are social insects and live underground in colonies. They attack young seedlings as well as grown up plants. The attacked plants wither and ultimately die. The use of partially decomposed manure should be avoided. Seed treatment with Chloropyriphos 20 EC @ 4-5 ml per kilogram seed or Endosulfan 35 EC @ 2.5 ml per kilogram seed is recommended. Mixing of Endosulfan or methyl parathion or Quinalphos dust@ 25 kg/ha before sowing in soil is very effective. In standing crop Chloropyriphos 20 EC @ 2 litres per hectare may be used with irrigation water.

2-Wheat aphids

The nymphs and adults of wheat aphids (Macrosiphum miscanthi) suck sap from leaves, tender shoots, immature grains and result in poor yield. Aphids multiply very fast, forming large colonies. Heavily manured, well-irrigated and succulent crop will harbour the pest for a longer period and suffer greater damages.

Important Pests of Gram

1-Gram cutworm

The caterpillar of gram cutworm (Agrotis ipsilon) feeds on young leaves and cuts the stem at the ground level. It can be controlled by summer ploughing and application of methyl parathion 2% dust @ 25 kg/ha. Gram pod borer: The caterpillar of gram pod borer (Heliothis armigera) feeds on young leaves and pods. It makes holes in pods and eats developing seed. A single larva may destroy 30-40 pods before it reaches maturity. It can be controlled by hand picking at early stage and spraying Endosulfan 35 EC @ 0.05%.

Important Pests of Red gram

1-Tur pod bug

Both adults and nymph (Clavigralla gibbosa) suck cell sap from the stem, leaves, flower buds and pods. The pods turn pale yellow and grains get shrivelled. The yield is reduced significantly. It can be controlled by spraying Endosulfan 35 EC @ 0.05%. Red gram pod fly: Maggots of red gram pod fly (Melangromyza obtusa) feed on seeds and make the grain unfit for consumption. It can be controlled by spraying Endosulfan 35 EC @ 0.05%. Plume moth borer: Plume moth borer (Exelastis atomosa) is a specific pest of red gram. Greenish-brown hairy caterpillars feed on flowers and later on bore into pods to feed on the developing seed inside. It reduces the yield significantly. It can be controlled by dusting 4% Carbaryl or spraying 0.04 per cent Monocrotophos or 0.05 per cent Endosulfan.

Important Pests of Groundnut

1-White grub

The adults of groundnut white grub (Holotricha consanguinea) emerge immediately after monsoon. The grubs feed on roots and kill the plants, whereas the adult feeds on shrubs and the trees growing nearby the cultivated fields. Under severe grub infestation the entire crop is destroyed. It can be controlled by collection of beetles by shaking the trees and destroying the insect. The repeated ploughings, preferably soon after the summer rains, expose the white grubs to their natural enemies. Seed treatment of groundnut kernels with Chloropyriphos 15-20 ml/kg seed effectively protects the crop. The grubs may be controlled by soil application of Phorate 10 G @ 25 kg/ ha or Carbofuran @ 35 kg/ha.

2-Aphids

The adults of aphids (Aphis craccivora) are vectors of a viral disease (rosette). Colonies of nymphs and adults infest the tender growing shoots and flowers and suck the sap. The infested parts dry up. It can be controlled by spraying 0.03 per cent Dimethoate, Phosphamidon, Monocrotophos.

Important Pests of Mustard

1-Mustard aphids

Light green nymphs and adults of mustard aphid (Lipaphis erystmi) suck the sap from the leaves and other parts including inflorescences. Aphids also secrete honeydew, which drops on leaves and favour the growth of a black fungus or mould. Aphids are most active from December to February. Affected leaves get curled and plants wither and die. It can be controlled by growing early maturing varieties, practising clean cultivation, spraying 0.02 per cent Phosphamidon or 0.03 per cent Monocrotophos, methyl demeton or dimethoate. Mustard saw fly: Larvae of mustard saw fly (Athalia proxima) attack all – cruciferous crops and feed on the leaves of young seedlings. When the -attack is severe, they completely defoliate the plants, leaving only the midribs. It can be controlled by hand- picking the larvae. If the attack is severe, apply 5 per cent Carbaryl dust 25 kg/ha. The crop may also be sprayed with 0.02 per cent Phospha- midon.

2-Painted bug

Adults and nymphs of painted bug (Bagrada cruciferarum) damage rape, mustard and other cruciferous crops by sucking the sap and devitalizing the plants. This pest remains active from October to March. It can be controlled by collecting and destroying the bugs; dusting the crop with Carbaryl 4 per cent dust @ 25 kg/ ha; spraying 0.02 per cent Phosphamidon or 0.03 per cent Dimethoate or Malathion.

Important Pests of Sugarcane

1-Shoot borer

Larvae of shoot borer (Chilo infuscatellus) tunnels into the stem, causing dead-heart, and as a result 10- 15 per cent of canes are usually damaged. After formation of canes the attack does not produce dead-hearts and the damage is confined to a few internodes only. It can be controlled by collection and destruction of Infested tillers; using higher seed rate; trash mulching: growing resistant varieties like Co 853, Co 997, Co 1007 and sprinkling 2 litres BHC 20 ЕС ог Heptachlor 20 EC in 400 to 600 litres water on cane setts placed in furrow, or application of Phorate 10% G @ 25 kg/ha at 35 days of planting.

2-Top borer

The top borer (Tryporyza nivella) accounts for 10-30 per cent reduction in yield, resulting in low Juice quality and early maturity of the crop. The newly hatched larva enters the midrib of the leaf and travels downwards and bore into the central yellow whorls of leaves, causing dead- hearts, which begin with a few short holes in central leaf sheath. A black streak of fresh excreta runs from the top towards the interior. It appears as if the central leaf sheath of plant has been burnt and shot. When central shoot has been damaged, side shoots develop, which is known as bunchy top. It can be controlled by growing resistant variety e.g. Co 419, and soil application of Carbofuran 12 kg a.i./ha.

3-Leaf hopper

Sugarcane leaf hopper (Pyrilla perpusilla) remains in colonies on the lower surface of leaves, and both the adults and nymphs, suck up. the sap causing yellowing and drying of leaves. Even the canes dry up and die when the attack is very severe. Under epidemic conditions, nearly 50 per cent decrease in sugar recovery occurs and gur will not be set. The insect secrete a thick transparent liquid, known as honeydew, which falls on the leaves and makes a good medium for the growth of black mould. It can be controlled by spraying Malathion @ 0.01%.

Important Pests of Cotton

1-Cotton aphids

Cotton aphid (Aphis gossypii) infests the tender shoots and undersurface of leaves in very large number and sucks the sap. Severe infestation results in leaf curling, stunted growth and gradual drying and death of young plants.

2-Spotted bollworm

Larva of spotted bollworm (Earias insulana) causes drooping and drying of the shoot due to its feeding into it. In later stage buds, flowers and bolls are damaged. The attacked buds and bolls are shed excessively. It can be controlled by removing and destroying the infested portion and periodical spray of Carbaryl 50 WP @ 1 kg/ha or 500 ml Ripcord 10 EC or 200 ml Permasect 25 EC or 1 litre Endosulfan 35 EC per hectare.

3-Pink bollworm

The caterpillar of pink bollworm (Pectinophora gossypiella), which bores the shoot, buds, flower, bolls and seed of cotton leads to their shedding. The young larvae enter the developing bolls through the tip; and entrance hole get closed up as the boll matures. Infestation causes retardation of lint development and weaken the lint. It can be controlled by periodical spray of chemicals recommended for spotted bollworm and collection and destruction of infested portions.

4-Red cotton bug

The nymphs and adults of red cotton bug (Dydercus cingulatus) suck the sap from the bolls, which if attacked young remain stunted, yielding poor cotton. Fibre is stained and seed becomes worthless for sowing.