Corn Rootworm Larvae
Corn Rootworm Larvae

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*This is an excerpt from Scouting Techniques for Soil Insect Pests of Peanuts, ANR-1364

Wireworms have become the major insect pest of peanuts under certain cropping conditions. Several species of wireworms occur in peanut fields, so an independent description for all species is not provided in this publication. Wireworms can cause significant late-season loss of peanut pods. Overwintering stage: Larvae overwinter in soil and move deep into it to prevent dehydration and reduce threat from natural enemies. Wireworms have an extended life cycle (2 to 9 years), depending on the species. Behavioral clues: Good mobility of larvae makes management of the insect very difficult. Larvae prefer soil moisture in the range of 6 to 16 percent and become immobile at low soil temperatures. Wireworms are also infamous for their behavioral resistance (i.e., many species have the ability to avoid insecticide-treated areas resulting in control failure).

Scouting Techniques

• Sampling. Wireworm larvae make a large entry hole on the distal end of pods. Pod injury could be highly clumped (nonuniform), so draw a large number of pod samples from different parts of the field for high sampling accuracy.

• Germinating seed baits. Fields with a history of infestations should be intensively scouted before planting. The most reliable sampling method is with germinating seed baits placed in soil. Wireworms are attracted to the carbon dioxide and heat released by germinating seeds in ground baits. Note that the attractiveness of seed baits varies with wireworm species (e.g., corn/wheat seed bait are attractive to Agriotes and Melanotus sp., and sorghum seed baits are attractive to Conoderus sp.).

• Pitfall traps. These have been very effective for catching surface-dwelling click beetles (i.e., adult wireworms). Several pitfall traps (plastic cups filled one-third with soapy water) should be deployed in suspected fields, especially between the peanut rows, and traps should be marked with tall flags to increase visibility. Action threshold: One or more wireworms from each bait station indicate a need for treatment.

Read here to learn more about Scouting Techniques for Soil Insect Pests of Peanuts.

 

*This is an excerpt from Scouting Techniques for Soil Insect Pests of Peanuts, ANR-1364

The lesser cornstalk borer (LCB), Elasmopalpus lignosellus, is one of the major insect pests of peanuts in some parts of Alabama. Overwintering stage: Larvae overwinter in soil and crop debris.

Behavioral clues: Research indicates that LCB is better able to survive dry soil conditions in which its natural predators cannot thrive. This anomaly results in a greater incidence of LCB in the soil. Larvae of this insect are highly attracted to carbon dioxide and heat released by belowground plant parts of peanuts.

Scouting Techniques

• Scouting maps. It is very important to detect this insect early in the season so that control measures can be undertaken in a timely manner. Scouting maps are available for LCB through the AWIS Weather Services Web site. Based on calculation of borer days (BD), there will be a need to scout if the model has values within a 0 to 5 range. BD values over 5 indicate unusually high larval populations.

• Pheromone traps. These are highly effective in detection and monitoring of flight activity of adults. Preliminary data from the 2009 IPM pheromone trapping project in Alabama indicate that moth flight initiate in June followed by several weeks of intense mating activity in July and August. High and dry areas in sandy fields should be monitored closely for crop injury because LCB larvae survive well under xeric conditions.

• Look for webbing. Pull some pods out of the ground and look for webbing  attached to damaged pods. Larvae make feeding tubes that can be easily detected. Action threshold: Presence of larvae in 30 percent of sampling sites suggests economically injurious populations.

Read here to learn more about Scouting Techniques for Soil Insect Pests of Peanuts.

 

 

 

*This is an excerpt from Citrus Pest Identification and Management Guide, ANR- 2270.

The most characteristic symptom of HLB is blotchy mottling that appears asymmetrically on the leaf blade. Green islands may also occur; these are small, circular, dark green dots that contrast with the light yellow/green background. Foliar symptoms that resemble nutrient deficiencies may be present. A tree may exhibit yellow shoots or other nutrient deficiency symptoms on one or more branches randomly in the canopy. Fruit may be small and lopsided or ripen backward, with the stylar end remaining green as the fruit colors.

Management tips: Citrus greening has not been found in Alabama to date. If citrus greening is suspected, contact your local diagnostic lab.

 

Read more about Citrus Pest Identification and Management Guide.

Download a PDF of Citrus Pest Identification and Management Guide, ANR- 2270.

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