Introduction to Major Field Crops

Plant Protection

Insect Pests
Gram has relatively a few insect-pests when compared with most other semi-tropical leguminous crops because;

1. The plants are covered with glandular hair which exude acid-droplets containing high concentration of malic acid, so insects appeared to be deterred by this very acidic (pH 1.3) exudate and,
2. As this crop is normally sown before or just after the winter in almost all areas of the world in which it is of importance, it grows during the period when insect activity and population are at a minimum.


Gram Pod Borer: The gram pod borer is the most serious pest of gram and causes the yield reduction up to the extent of 75 per cent. The control measures are as follows.

• Use of resistant varieties such as ICC 506, ICC 6863, PDE 2, AKG 33, Pant CE 1, BG 256, etc.
• Early sowing in north and central India (15-30 October).
• Intercropping gram with mustard, wheat, safflower and barley.
• Use of insecticides, spray of Endosulfan (0.07%) or Monocrotophos (0.04%) or Chloropyriphos (0.05%) solution. Use of neem based bio-pesticides @5.0 per cent solution.
• For biological control, use of NPV and Bacilluisthurigiensisare found to be effective.



Fig: Gram pod borer.


Gram Cutworm: The gram cutworm is a serious pest in low-lying areas where fields are clody. Dusting Endosulfan @ 20 kg/ha or mixing of Endosulfan in the soil @ 20-25 kg/ha is effective in controlling the pest.

Termites: Soil and seed treatment with Chloropyriphos is effective against termites.Maintaining the optimum soil moisture reduces the infestation of termites as the attack of termites is severe in dry soils.

Diseases
Blight: It is the most serious disease of gram between the latitudes 30° and 45° where relatively lowtemperature (15-25°C) prevails during the crop season. Diseased debris and infected seeds are the main source of inoculum.Control measures include;

• Use resistant varieties namely, BG 261, BG 280 and H 75-35 (Gaurav).
• Removal and destruction of dead debris.
• Crop rotation.
• Deep sowing.
• Intercropping gram with wheat, barley and mustard.
• Advancing the sowing date in autumn.
• Seed treatment with Thiram or Captan (0.25%) or with Bavistin + Thiram combination @ 250 g/q of seed.
• Foliar spray – four protective sprays with Captan or Zineb@ 2.5 kg/ha at 10-15 days interval or Bordeaux mixtures spray.


Fusarium Wilt: It is prevalent in the entire gram growing areas of India. The young growing tips of diseased plants become limp and drooping. The leaves start withering due to inadequate water supply and excessive transpiration. On splitting open the taproot lengthwise, dark-brown fungus streaks can be seen in the root near the pith region. The pathogen enters the root system and xylem vessels, thereby reducing water supply to the plant.

As far as possible, early sowing of gram should not be takenbefore third week of October. Deep planting of about 8-10 cm deep in the light soils reduces the wilt incidence.Resistant varieties such as ICC 202, ICC 391, Pant G 114, Pusa 209 and C 235 should be grown.Seed treatment with Bavistin(25%) +TMTD (50%)@250 g/q of seed reduces the incidence of wilt.

Dry Root Rot: The taproot on pulling out is found to be devoid of bark and lateral roots. The dead root is dry and brittle towards the tip. Black sclerotic bodies of the fungus can be seen on the main root below the bark.Early sowing of early maturing cultivars with timely irrigation minimizes the disease. Seed should be treated with Captan or Thiram or PCNB @ 2.5 g/kg seed.