Taking an environmentally sensitive approach to pest management


Integrated Pest & Crop Management



AUTHOR

Wayne C. Bailey
University of Missouri
Division of Plant Sciences
(573) 882-2838
baileyw@missouri.edu

Small Grasshoppers Numerous in Many Areas of Missouri

Wayne C. Bailey
University of Missouri
(573) 882-2838
baileyw@missouri.edu

Published: July 5, 2010

Several regions of Missouri are experiencing high numbers of small grasshoppers. Historically wet years have not favored grasshopper populations as high moisture levels tend to allow bacterial and fungal pathogens to attack developing grasshopper nymphs. This has changed in the past 5 years as grasshopper populations tend to build whether wet conditions are present or not. The economic thresholds for grasshoppers vary depending on the commodity or non-cropland area requiring insecticide applications for effective grasshopper management. In Missouri, there are approximately 100 species of grasshoppers although only 5-7 species are common in field crops. Although there is conflicting data, most entomologist believe that smaller grasshoppers (small nymphs) are more easily controlled with insecticides than larger nymphs or adult hoppers. As with most insects, the larger the hoppers grow, the more foliage and other plant materials they consume. Damage from both nymph and adult grasshoppers is often seen as very ragged feeding wounds located on leaf edges. In severe situations, high numbers of grasshoppers can consume large amounts of vegetation and cause substantial loss of grain and forage yields. Economic threshold information is listed with each of the following commodity tables.

Table 1. Grasshoppers in Alfalfa
Comments: Control grasshoppers when they are small by applying spot treatments to hatching sites in non-cropland areas. Treatment in these areas is justified when grasshopper numbers reach or exceed 15 grasshippers per square yard.
Common Name Trade Name Rate of Formulated Material per acre Placement
esfenvalerate *Asana XL 2.9 to 5.8 fl oz Broadcast
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl oz Broadcast
carbaryl Sevin XLR Plus 1 to 3 pt Broadcast
lambda-cyhalothrin *Warrior 2.56 fl oz, see dealer for rates Broadcast

 

Table 2. Grasshoppers in Field Corn
Comments: Control grasshoppers when they are small by applying spot treatments to hatching sites in field borders and grass waterways. Treatment is justified in corn field when 7 or more grasshoppers per square yard are present and foliage is being severely damaged. After pollen shed, control may be necessary if grasshoppers are damaging foliage above ear zone. Dimethoate should not be applied to corn during pollen-shed.
Common Name Trade Name Rate of Formulated Material per acre Placement
esfenvalerate *Asana XL 5.8 to 9.6 fl oz Broadcast
cyfluthrin *Baythroid XL 2.1 to 2.8 fl oz Broadcast
bifenthrin *Brigade 2EC 2.1 to 6.4 fl oz Broadcast
chlorpyrifos +
gamma-cyhalothrin
*Cobalt 7 to 13 fl oz Broadcast
dimethoate Dimethoate 4EC 1 pt Broadcast
bifenthrin *Fanfare 2EC 2.1 to 6.4 fl oz Broadcast
zeta-cypermethrin +
bifenthrin
*Hero 2.6 to 6.1 fl oz Broadcast
chlorpyrifos *Lorsban 4E 1/2 to 1 pt Broadcast
zeta-cypermethrin *Mustang Max 2.72 to 4.0 fl oz Broadcast
chlorpyrifos *Nufos 4E 1/2 to 1 pt Broadcast
microencapsulated
methyl parathion
*Penncap-M 2 to 3 pt Broadcast
lambda-cyhalothrin *Proaxis 2.56 to 3.84 fl oz Broadcast
carbaryl Sevin XLR Plus 1 to 3 pt Broadcast
lambda-cyhalothrin *Warrior 2.56 to 3.84 fl oz Broadcast

 

Table 3. Grasshoppers in Grass Pastures
Comments: Control grasshoppers when they are small by applying spot treatments to hatching sites or in grass pastures. Treatment in these areas is justified when grasshopper numbers reach or exceed 7 grasshoppers per square yard.
Common Name Trade Name Rate of Formulated Material per acre Placement
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl oz Broadcast
carbaryl Sevin XLR Plus 1 to 4 pt Broadcast
lambda-cyhalothrin *Warrior 2.56 to 3.84 fl oz Broadcast

 

Table 4. Grasshoppers in Non-Cropland Areas
Comments: Control grasshoppers when they are small by applying spot treatments to hatching sites in non-cropland areas. Treatment in these areas is justified when grasshopper numbers reach or exceed 15 grasshoppers per square yard.
Common Name Trade Name Rate of Formulated Material per acre Placement
esfenvalerate *Asana XL 2.9 to 5.8 fl oz Broadcast
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl oz Broadcast
carbaryl Sevin XLR Plus 1 to 3 pt Broadcast
lambda-cyhalothrin *Warrior 2.56 fl oz, see dealer for rates Broadcast

 

Table 5. Grasshoppers in Sorghum (milo)
Comments: Control grasshoppers when they are small by applying spot treatments to hatching sites in field borders and grass waterways. Treatment in field is justified when 7 or more grasshoppers per square yard are present
Common Name Trade Name Rate of Formulated Material per acre Placement
cyfluthrin *Baythroid XL 2.0 to 2.8 fl oz Broadcast
chlorpyrifos +
gamma-cyhalothrin
*Cobalt 7 to 13 fl oz  
dimethoate Dimethoate 4EC 1/2 to 1 pt  
lambda-cyhalothrin Karate w Zeon Tech 1.28 to 1.92 fl oz  
chlorpyrifos *Lorsban 4E 1 to 2 pt  
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl oz  
chlorpyrifos *Nufos 4E 1 to 2 pt  
gamma-cyhalothrin *Proaxis 2.56 to 3.84 fl oz  
carbaryl Sevin XLR Plus 1 to 3 pt  
lambda-cyhalothrin *Warrior 2.56 to 3.84 fl oz  

 

Table 6. Grasshoppers in Soybean
Comments: Treat when defoliation reaches 30% before bloom, 20% bloom to pod fill, or when 5% to 10% of pods are damaged.
Common Name Trade Name Rate of Formulated Material per acre Placement
esfenvalerate *Asana XL 5.8 to 9.6 fl oz Broadcast
cyfluthrin *Baythroid XL 2.0 to 2.8 fl oz  
bifenthrin *Brigade 2EC 2.1 to 6.4 fl oz  
chlorpyrifos +
gamma-cyhalothrin
*Cobalt 7 to13 fl oz  
dimethoate Dimethoate 4EC 1 pt  
carbofuran *Furadan 4F 1/4 to 1/2 pt  
carbofuran *Furadan LFR 1/4 to 1/2 pt  
chlorpyrifos *Lorsban 4E 1/2 to 1 pt  
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl oz  
chlorpyrifos *Nufos 4E 1/2 to 1 pt  
acephate Orthene 97 1/4 to 1/2 lb  
microencapsulated
methyl parathion
*Penncap-M 2 to 3 pt  
permethrin *Pounce 3.2EC 2.0 to 4.0 fl oz  
lambda-cyhalothrin *Proaxis 3.2 to 3.84 fl oz  
carbaryl Sevin XLR Plus 1 to 3 pt  
lambda-cyhalothrin *Warrior 3.2 to 3.84 fl oz  

 

Table 7. Grasshoppers in Wheat
Comments: Treat when defoliation reaches 30% before bloom, 20% bloom to pod fill, or when 5% to 10% of pods are damaged.
Common Name Trade Name Rate of Formulated Material per acre Placement
cyfluthrin *Baythroid XL 1.8 to 2.4 fl oz On foliage
chlorpyrifos + *Cobalt 7 to 13 fl oz  
dimethoate Dimethoate 4EC 3/4 pt  
carbofuran *Furadan 4F 1/4 to 1/2 pt  
carbofuran *Furadan LFR 1/4 to 1/2 pt  
lambda-cyhalothrin *Karate 1.28 to 1.92 fl oz  
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl oz  
microencapsulated
methyl parathion
*Penncap-M 2 to 3 pt  
gamma-cyhalothrin *Proaxis 2.56 to 3.84 fl oz  
carbaryl Sevin XLR Plus 1 to 3 pt  
lambda-cyhalothrin *Warrior 2.56 to 3.84 fl oz  
Seed Treatments      
lambda-cyhalothrin *Proaxis 3.2 to 3.84 fl oz  
carbaryl Sevin XLR Plus 1 to 3 pt  
lambda-cyhalothrin *Warrior 3.2 to 3.84 fl oz  
*Designated a restricted use product. Use is restricted to certified applicators only. Regardless of the formulation selected, read the label to determine appropriated insecticide rates, directions, precautions, and restrictions.
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