This week with the early rice starting to head we are seeing a large population of rice stink bugs. In the verification we were catching almost 1 stink bug per sweep. Very high numbers are being reported throughout the parishes.
The rice stink bug is the second most important rice pest in Louisiana. They overwinter as adults in grass clumps, ground trash and woods. They emerge early in the spring and several generations can develop on grasses in and around rice fields.
As the rice begins heading, they move to the rice and begin feeding on the developing kernels. Adult rice stink bugs are shield-shaped, metallic brown insects about one-half inch long. Both nymphs and adults puncture the grain with their stylets and suck the juices. Grain fed on in the early milk stage fail to develop normally and empty glumes or shriveled grain results. Grains fed on in the dough stage may be weakened structurally and break in the filling process or if infected with a fungus, develop a black spot or pecky rice. Damage can result in reduced yield, reduced milling quality and lower grade.
Rice fields should be monitored weekly beginning immediately after pollination until kernels begin to harden. Random sweep net samples should be taken in each field, and the total number of rice stink bugs collected should be recorded. During the first two weeks of heading, fields where 30 or more stink bugs are taken per 100 sweeps should be treated. In the later stages of heading, fields should be treated when 100 or more stink bugs are taken per 100 sweeps until two weeks before harvest. Scout in the morning for best results.
Chemicals recommended for rice stink bug control includes:
Insecticide Dosage Per Acre Active Ingredient
Penncap-M .75 - .5 lbs A.I./Acre
ProAxis .0125 - .02 lb A.I./Acre
Prolex .0125 - .02 lb A.I./Acre
Mustang Max .0165 - .025 lb A.I./Acre
Malathion 57% EC .6 - .9 lb A.I./Acre
Sevin 805 1 1/4 - 1 7/8 lb product per acre
Sevin 4F 1 – 1 ½ qts. Product per acre
Methyl Parathion 4EC 3/4 lb. A.I./Acre
Karate Z .025 - .04 lb. A.I./Acre
Declare .0125 - .02 lb. A.I./Acre
Remember, as always, follow label instructions.
I am also seeing some grasshopper damage on the rice that is just heading. The grasshoppers are feeding on the developing grain. The kernels that are being fed on will abort and not fill. Very rarely do we need to treat just for grasshoppers but if they are severe a treatment may be necessary. All of the insecticides listed above except for Malathion and Sevin are labeled for grasshoppers, however; some of the rates are different. Please be sure to read the label for the correct rates.
Also, don’t forget the LSU AgCenter Rice Research Station Rice Field Day will be held on Thursday, July 1, 2010, at the Station. The activities will begin at 7:30 a.m. with field tours of research projects, with the last tour truck leaving no later than 9:15 a.m. There will be a poster session under the equipment shed on the west side of the drier from 7:30 to 10:30 a.m. Much of the program will focus on historical aspects of technology developed through the years at the research facility. The main program will start at 10:45 a.m., with a lunch following.
As always if you need any help or information please call at 788-8821.