Lesser Corn Stalker
Lesser Corn Stalker

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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 southern corn rootworm (SCRW), Diabrotica undecimpunctata howardi, is the immature form of the spotted cucumber beetle. Overwintering stage: Beetles diapause in November, but the diapause is short and they could emerge quickly the following season. Research indicates that most overwintering populations consist of female beetles that oviposit the following year.

Behavioral clues: Larvae do not make webs, so feeding injury from smaller instars may not be evident on the pods. The adult beetle is highly migratory and a strong flyer.

Scouting Techniques

• Larval infestations. Infestations in the soil should be thoroughly scouted close to the pegging stage. Remember that high soil moisture and poorly drained soils are favorable for the buildup of this insect. Initiate control measures when rootworm larvae are found in 30 percent of sample locations.

• Pheromone traps. These can be used to monitor beetle activity. Pheromone traps for this insect are available commercially as easy assembly kits. According to industry sources, trap catches of over 100 beetles per trap per week is indicative of high insect activity that should be investigated further by direct crop scouting and soil sampling for active larvae to estimate pod damage. Note that larval activity in soil may lag behind adult emergence and mating period.

• Sweep netting. This is a reliable sampling method for SCRW beetles. Collect a sample by making ten sweeps over the crop canopy in ten paces, and repeat this step from five locations per acre (collect representative samples from several random locations). Sweep net sampling should be done mid-morning because afternoon heat could move the insects deep into the crop canopy, thereby reducing sampling accuracy. If feasible, check the plant canopy for the actual number of adult beetles present on entire plants and compare the accuracy of sweep net samples.

• Check for holes. Check the pods for small to mediumsized circular holes at one end of the pod. In some instances, larvae make a series of entry holes all in one area of the pod.

• Risk index. Although SCRW infestations are sporadic, peanut producers may use the “risk index” developed by North Carolina State and Virginia Cooperative Extension to gain more experience about risk factors. SCRW risk index incorporates factors such as cultivar resistance, soil texture, soil moisture, field history, and planting date. Action threshold: Presence of adult or larvae or fresh damage in one-third of sampling sites indicates need for treatment.

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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