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

Grasshopper Nymphs Present in Missouri

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

Published: July 27, 2009

Grasshopper nymphs can be found throughout Missouri. Typically a summer pest on field crops, the wet conditions in most areas of the state have allowed for the buildup of this pest in the lush, green vegetation of field borders, waterways, and in no-till fields. At present grasshopper nymphs range from very small in size up to 1/2 –inch in length. Wet years usually do not favor grasshopper populations as fungal pathogens can cause high mortality of small grasshoppers. This year the wet weather has not helped with grasshopper mortality, possibly allowing for grasshopper populations to build to problem levels. In Missouri, over 100 grasshopper species can be found although 6-7 species may cause problems in field crops. Typical grasshopper damage consists of irregular shaped holes extending from the leaf margin to the center of the leaf. Damaged tissue surrounding the feeding wound often has dead tissue surrounding the wound. Grasshoppers are capable of doing considerable damage in a very short time, especially at they grow in size. Adult grasshoppers (winged) are more difficult to control than smaller nymphs (wingless).

The following table lists the economic threshold for grasshopper infestations in non-cropland areas and grass pastures, corn, soybean, grain sorghum (milo) pesticide label directions and precautions.

Table 1. Grasshoppers in Non-Cropland Areas
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
lambda-cyhalothrin *Warrior 2.56 to 3.84 fl. oz. Broadcast
* Designates a restricted-use pesticide. Use is restricted to certified applicators only. Regardless of the formulation selected, read the label to determine appropriated insecticide rates, directions, precautions, and restrictions.

 

Table 2. Grasshoppers in Grass Pastures
Grasshoppers in Grass Pastures
Comments: Control grasshoppers when they are small by applying spot treatments to hatching sites 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
* Designates a restricted-use pesticide. Use is restricted to certified applicators only. Regardless of the formulation selected, read the label to determine appropriated insecticide rates, directions, precautions, and restrictions.

 

Table 3. Grasshoppers in Field Corn
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 fields when 7 or more
grasshoppers per square yard are present and grain fill is being severely limited. 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
microencapsulated methyl parathion *Penncap-M 2 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
* Designates a restricted-use pesticide. Use is restricted to certified applicators only. Regardless of the formulation selected, read the label to determine appropriated insecticide rates, directions, precautions, and restrictions.

 

Table 4. Grasshoppers in Soybean
Grasshoppers in Soybean
Comments: Treat when defoliation reaches 30% before boom, 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. 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
carbofuran *Furadan 4F 1/4 to 1/2 pt. Broadcast
carbofuran *Furadan LFR 1/4 to 1/2 pt. Broadcast
chlorpyrifos *Lorsban 4E 1/2 to 1 pt. Broadcast
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl. oz Broadcast
chlorpyrifos *Nufos 4E 1/2 to 1 pt. Broadcast
acephate Orthene 97 1/4 to 1/2 lb. Broadcast
microencapsulated methyl parathion *Penncap-M 2 to 3 pt. Broadcast
permethrin *Pounce 3.2EC 2.0 to 4.0 fl. oz Broadcast
lambda-cyhalothrin *Proaxis 3.2 to 3.84 fl. oz Broadcast
carbaryl Sevin XLR Plus 1 to 3 pt. Broadcast
lambda-cyhalothrin *Warrior 3.2 to 3.84 fl. oz. Broadcast
* Designates a restricted-use pesticide. Use is restricted to certified applicators only. Regardless of the formulation selected, read the label to determine appropriated insecticide rates, directions, precautions, and restrictions.

 

Table 5. Grasshoppers in Grain Sorghum
Grasshoppers in Grain Sorghum
Comments: Control grasshoppers when they are small by applying spot treatments to hatching sites in grain sorghum. Treatment in field is justified when 7 or more grasshoppers per square and are present.
Common Name Trade Name Rate of Formulated Material per acre Placement
cyfluthrin *Baythroid XL 1.0 to 2.8 fl. oz. Broadcast
chlorpyrifos + gamma-cyhalothrin *Cobalt 7 to 13 fl. oz. Broadcast
dimethoate *Dimethoate 4EC 1/2 to 1 pt. Broadcast
lambda-cyhalothrin Karate w/ Zeon Tech 1.28 to 1.92 fl. oz. Broadcast
chlorpyrifos *Lorsban 4E 1 to 2 pt. Broadcast
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl. oz Broadcast
chlorpyrifos *Nufos 4E 1 to 2 pt. Broadcast
gamma-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
* Designates a restricted-use pesticide. Use is restricted to certified applicators only. Regardless of the formulation selected, read the label to determine appropriated insecticide rates, directions, precautions, and restrictions.

 

Table 6. Grasshoppers in Wheat
Grasshoppers in Wheat
Comments: Treat when 8 or more adults per square yard are present within crop. Barrier treatments in border areas may be required to prevent migration into the crop if more than 20 adults per square yard are present in field margins.
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. On foliage
dimethoate *Dimethoate 4EC 3/4 pt. On foliage
carbofuran *Furadan 4F 1/4 to 1/2 pt. On foliage
carbofuran *Furadan LFR 1/4 to 1/2 pt. On foliage
lambda-cyhalothrin *Karate 1.28 to 1.92 fl. oz. On foliage
zeta-cypermethrin *Mustang Max 3.2 to 4.0 fl. oz. On foliage
microencapsulated methyl parathion *Penncap-M 2 to 3 pt. On foliage
lambda-cyhalothrin *Proaxis 2.56 to 3.84 fl. oz. On foliage
carbaryl Sevin XLR Plus 1 to 3 pt. On foliage
lambda-cyhalothrin *Warrior 2.56 to 3.84 fl. oz. On foliage
Seed Treatments      
* Designates a restricted-use pesticide. 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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REVISED: February 29, 2012