Field Guide     Pest Management     Whitefringed Beetles

Whitefringed Beetles

CROPS IMPACTED: tobacco, cotton, peanuts, velvetbeans, potatoes, soybeans

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Family: Curculionidae

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About Whitefringed Beetles

Reproduction and Life Cycle

This pest has one generation per year. They spend the winter as larvae, and occasionally as eggs; however, the eggs have a harder time surviving the winter unless they are in an area protected from the harsh conditions of winter. Larvae emerge in the early spring and feed on roots or underground stems of host plants. They will then tunnel deep into the ground, usually 5 to 15cm, and pupate. This stage lasts 13 days. The adults then surface and begin eating foliage. Oviposition takes place 5 to 25 days following emergence. The eggs are laid in clusters of around 15 on host plant stems, roots, or in the soil. If the eggs hatch during the summer, it takes about 17 days. If; however, the eggs overwinter, it can take about 100 days for them to hatch. The total number of eggs each female lays depends on what they fed on. Beetles with a diet consisting of mainly legumes can lay more eggs than those with a diet of grass.

Whitefringed Beetles Identification and Habitat

Identification

Adults are brown to black in colour with a band that runs along the edge of the beetles wing covers lighter in color than the body. There are also two light colored stripes that run down either side of the head and thorax. They are about 12mm in length with gray-brown scales that cover the body. This beetle is flightless and is only female. The eggs are oval in shape and start off white, turning pale yellow near the time of hatching. They are 0.9mm in length, and 0.6mm in width. When first laid the eggs have a tacky coating that will harden as it matures. The larvae are curved, pale yellow, and are without legs. Their heads are tan to brown; larvae can grow to be about 13mm. The pupae are the same length as larvae and are white in color, but will darken as time passes.

Habitat

The whitefringed beetle is native to South America, now with a presence in many parts of the southern United States. This beetle has been reported attacking close to 400 different plant species, although it tends to prefer types such as peanut, cotton, soybean, sweet potato, and velvetbean. Typically any species with broad, large leaves that are smooth in texture and those that have taproots are the chosen variety. Sometimes small grains are attacked; however, due to their tough root system, they can withstand the damage more effectively. This pest tends to not cause a significant amount of damage when the adults feed on foliage, often only leaving ragged cuts along the edges of the leaves. However, when the larvae feed on taproots and stems underground, considerable injury is likely to occur. Symptoms to look for include the yellowing of leaves, and wilted plants. Severely damaged plants will die

Whitefringed Beetles Management and Control Methods

Cultural Control

To help manage the whitefringed beetle, rotate crops with small grains or oats, as they are less preferred by this pest and have a high tolerance to injury caused by larvae due to their strong root system. Also, limit the amount of legumes planted, such as peanuts and soybeans, and put all legumes on a crop rotation of 3 to 4 years. This can help keep the whitefringed beetle population to a minimum. Disking before planting can also help injure larvae and expose them to natural predators such as birds. However, it is important to note that having satisfactory control is often dependent on using an integrated management system that includes the use of both cultural and chemical methods.

Chemical Control

When chemical control is needed for commercial crops such as sweet potato, phosmet (Imidan) has shown success when the formula is applied 1.33lb per acre. This pesticide should not be applied more than 5 times in a season. Not many other chemical are known to effectively control this pest in field crops. Be sure to always read the label for cautions and proper application. It is extremely important to never spray on days that are windy. After applying insecticides, irrigate sprayed area to increase the insect control. That being said, a large rainfall or irrigation soon after the application can reduce the concentration of insecticides.

Latin / Alternative Whitefringed Beetles Names

  • - Naupactus leucoloma

Sources

http://entnemdept.ufl.edu/creatures/field/beetles/whitefringed_beetles.htm

http://content.ces.ncsu.edu/insect-control.pdf

http://ipm.ncsu.edu/AG271/tobacco/whitefringed_beetle.html