The very dry summer conditions we have been experiencing are prime grasshopper growing weather. I am getting spotty reports of heavy 'hopper infestations in southeast and western parts of the county. The grasshoppers are already mature and flying, which makes them more mobile. The ones I have personally seen seem to be the differential grasshopper, which is one of the most destructive to crops/pasture land of the 'big five' species of grasshoppers of economic importance found in the state.
If you have been on the receiving end of this rainfall of late, I want to tell you to be on the lookout for Fall Armyworms in the near future. To a pregnant armyworm moth flying north from drought-ridden central Texas, our area is going to look like an oasis, prime territory to lay her eggs. I have already heard reports of Fall Armyworms near Sulphur Springs so I think it is just a matter of time before we have them in our area too.
If you have grasshoppers, the economic threshold of treatment is more than 8 grasshoppers per square yard (or as I like to say, 1 per square foot). Anything above 1 per square foot means that the 'hoppers are consuming more dollars worth of forage than it would cost in insecticide to treat them. The good news is that we typically see only one generation of grasshoppers per year.
If you find yourself with Fall Armyworms, the economic threshold of treatment is more than 3 young armyworms per square foot. If you have more forage than you need (which is unlikely) then you should probably consider skipping the cost of the treatment. However, if you have fertilized warm season pastures and are awaiting another hay cutting, treat if the armyworm load climbs above 3 per square foot. If you plant winter pastures, definitely treat when numbers justify as these insect pests can have more than one generation per year in our area and just might stick around until first frost if weather conditions are favorable to their continued development.
Please note that trade names and retail prices listed below are for educational purposes only and that no specific endorsement of any product is intended or implied. Please note that there are also waiting periods for some products listed below that are required between application and grazing / cutting for hay. Follow all label directions and wear required personal protective equipment when handling pesticides and making pesticide applications.
Grasshopper Control Options:
Sevin, Malation, Mustang Max, & Dimilin (Too late for '09 as 'hoppers are past 3rd instar)
Armyworm Control Options:
Sevin (Carbaryl 4F), Mustang Max, Malathion 5EC, Methomyl (Lannate VL), Methyl parathion 4E, Tracer 4SC, & Intrepid 2F
Fact Sheets (Please defer to pesticide list above for differences between pesticides listed on site and those mentioned in the fact sheets):
Grasshoppers grasshoppers.pdf (2 MB)
Armyworms ArmywormFactSheet2008.pdf
