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Economic Threshold Levels of Insect Pests

A decision to use an insecticide should be made only when an insect population has reached or exceeded an economic threshold—that level of a pest population at which control is needed to prevent economic loss (that is, the projected cost of damage is greater than the cost of control).The utmost principles of an insect management program are scouting fields and basing control decisions on economic thresholds. Growers should incorporate scouting and the use of economic thresholds into their crop management plans. Economc thresholds of insect pests of General Crops, Vegetables & Orchards are given as under:




Brown Leaf Rust   % Incidence & Low-Med-High Intensity         Hopper  
5/ Leaf (In Summer)1/ Leaf (In Winter)10/ Inflorescence or Twig
Smut   % incidence       Scales   50 Scales / Leaf
Armyworm   On Appearance       Fruit Fly   10% Damage
Aphid   No Spray recommended       Mealy Bug   On Appearance
Helicoverpa   No Spray recommended       Mango Midges   10 spots/ Twig or Inflorescence


          Gall Farming Insect       10 Galls / Leaf
Armyworm   On Appearance       Malformation   Low-Med-High
Helicoverpa   3 Larvae/25 plants       Anthracnose   On Appearance
Termite   10% damage      


Cutworm   10% at initial stage       Citrus Psylla   6/ Leaf
Blight   Low-Med-High       Leafminer   10% affected leaves
Wilt   % incidence        Fruit Fly   10% affected fruits


          Withertip   Low-Med-High
Top Borer   10% Attacked Plants       Canker   Low-Med-High
Stem Borer   -do-      


Root Borer   -do-       Red Pumpkin Beetle  
1/ 10 Plants (at seedling stage)
1/ Plants (at crop stage)
Gurdaspur Borer   -do-       Hudda Beetle   4/ Plant
Pyrilla   3/Leaf       Fruit Borer   10%on Brinjal 5% on Tomato
Black bug   10/ sheath       Diamond Back Moth   3/ Leaf
Whitefly   10/ Leaf       Helicoverpa   5% Fruit Infestation
Mites   10/ Leaf       Fruit Fly   3 % Fruit Infestation
Toka   3-5/ Sweep of Net       Jassid   1/Leaf on Cucurbits, 2/ Leaf on Brinjal,
3/ Leaf on Melons
Mealy Bug   On Appearance      
5/Leaf on Cucurbits
2/Leaf on Chillies, Cowpeas
Termites   10% Damage       Aphid   5/Leaf
Rodents   5 Live Burrows/ Acre       Powdery Mildew   Low-Med-High
Diseases   Only Presence       Downy Mildew   Low-Med-High


Only Seed Treatment
Shoot fly   5%            
            Root Rot    Only Seed Treatment
Stem borer   5%            
            Collar Rot   Water must not touch the stem
Helicoverpa   5 % Cobs            
            Leaf Spot/ Blight   Spray on appearance
Armyworm   On Appearance            






            Jassid   1 Adult or Nymph per leaf
Jassid   3/Leaf            
Blight   On Appearance       Whitefly   5 Adult or Nymph or both per leaf


          Thrips    8-10 Adult or Nymph per leaf
Cutworm      3% Attacked Plants       Cotton Mealy Bug   On Appearance

Oilseed Crops

          Mites   10-15 per leaf
1/ Pod10/ Twig
      Spotted Bollworm   3 Larvae/ 25 plants


          Pink Bollworm   5 Larvae/ 100 Bolls
Helicoverpa   1/5 Flowers       Helicoverpa   5 Brown eggs or 3 small larvae or Both 5 / 25 plants


          Armyworm   On Appearance
No. of Moths/Trap/Night  are 8-10 at Crop
Dead Hearts 5 % at Crop
      Aphid   Spray on visible damage on top terminals
Chrotogonous (Toka)
  3-5 Adults/Net            


Fruit Fly   10% Attacked Fruits (4-5 pheromone traps/ acre