Pod Feeding Insects -- Is Control Justified?
Steve L. Brown, Extension Entomologist
In the early 1990s, almost 60% of Georgia's peanut acreage was being treated with either Lorsban 15G of Dyfonate 15G. At that time, the decision to treat was based on the white mold suppression characteristic of these products as well as control of soil insects such as lesser cornstalk borers, wireworms and southern corn rootworms. Since the registration of Folicur, Moncut and now Abound for white mold control, the relatively weak disease suppression provided by Lorsban and Dyfonate is no longer a strong argument for their use. Consequently, the use of soil insecticides on peanuts has declined sharply in the last three years. Last year, Zeneca Ag Products announced the discontinuation of Dyfonate and that product is no longer available.
Where full rates of Folicur, Moncut or Abound are used, soil insecticides give little or no additional help with white mold. In situations where partial white mold control are used, they may still have some value as fungicides, but for the most part, the decision to use Lorsban or not should be based on its insecticidal properties.
Pod damage due to soil insects can be found in almost all peanut fields, but control of low levels of damage are not economically justified. In cases where soil insects are causing economic damage, lack of control can cost growers several hundred pounds of peanuts per acre. A good rule of thumb is that saving two pods per foot of row will justify the cost of treatment. Growers should get in the habit of examining plants for soil insect damage to get some idea of the level of damage they are experiencing. Keep in mind that damaged pods decay and fall off the plant so you may not be seeing all pod damage when peanuts are dug.
Lorsban can be applied as a pre-plant incorporated liquid or as granules over the top of the row. It can be applied in a preventative manner or when soil insects are detected, but the results of rescue treatments are more variable. The decision to make a preventative application of Lorsban involves determining which fields are likely to have soil insect problems and which are not. See the 1995 Peanut Update for help with that decision.
Chlorpyrifos, the active ingredient in Lorsban 4E and Lorsban 15G, is now off patent and several generic products are on the market. Assuming there are no problems with the way the active ingredient is formulated, generic products should perform equally well.
Attention: Pesticide Precautions
1. Observe all directions, restrictions and precautions on pesticide labels. It is dangerous, wasteful and illegal to do otherwise.
2. Store all pesticides in original containers with labels intact and behind locked doors. "Keep pesticides out of the reach of children."
3. Use pesticides at correct label dosage and intervals to avoid illegal residues or injury to plants and animals.
4. Apply pesticides carefully to avoid drift or contamination of non-target areas.
5. Surplus pesticides and containers should be disposed of in accordance with label directions, to contamination of water and other hazards will not result.
6. Follow directions on the pesticide label regarding restrictions as required by State and Federal Laws and Regulations.
7. Avoid any action that may threaten an Endangered Species or its habitat.
Your county extension agent can inform you of Endangered Species in your area, help you identify them and, through the Fish and Wildlife Service Field Office, identify actions that may threaten Endangered Species or their habitat.
Trade names are used only for information. The Cooperative Extension Service, the University of Georgia College of Agricultural & Environmental Sciences, does not guarantee or warrant published standards on any product mentioned; neither does the use of a trade or brand name imply approval of any product to the exclusion of others that may also be suitable.