About Tobacco WirewormReproduction and Life Cycle The tobacco wireworm has one generation annually. They overwinter as larvae in different instars, usually in the soil or among plant debris. In the spring when corn or tobacco seeds begin to germinate, the larvae will feed on the seeds and the new seedlings. Pupation will then occur by the roots underneath the soils surface. This development stage lasts only about 10 days. The adults emerge and within 13 days will begin to lay their eggs. On average, a female will lay 240 eggs and will place each one of them singly in the soil. The eggs take 10 days to hatch. The new larvae will begin feeding on host plant roots until it comes time to overwinter. Larvae will often stay in this stage of development for 315 days. Tobacco Wireworm Identification and HabitatIdentification Adults of the tobacco wireworm are click beetles. They are oblong, and have an average length of about 8.5mm. They have distinct brown markings on their back. Their general colour is red-brown. The end of the thorax has pointed corners. The eggs are white, 0.5mm wide, and are shaped like a sphere. New larvae are white and 1.5mm in length. Once they mature, they can be as long as 19mm. They become yellow to rust brown in colour, are hard, cylindrical and smooth. They have 6 legs located behind the head. Its final segment of the abdomen is a notch in the shape of a V. The pupae are brown and somewhat larger in size to that of an adult. Habitat Tobacco wireworms are typically found in the southeastern states. They mainly congregate in areas that have large quantities of corn and tobacco crops, especially in fields with a lot of weeds or grasses. While their main plant hosts tend to be tobacco and corn, they will also feed on potatoes and a variety of other plants. They mainly feed on seedlings, which can stunt the plant and can sometimes even kill the entire plant. Infected plants will often grow to have yellow streaking from its terminal blades. The adults also create irregular holes on the stem that is below the surface. This pest is more common in Coastal Plain and sandy soil, particularly when fields were not plowed after harvest during the fall. They are nocturnal, hiding just beneath the soils surface when the sun is out. They prefer humid and warm nights and are more active when these conditions are present. Tobacco Wireworm Management and Control MethodsCultural Control Due to the fact that this pest is quite unpredictable to judge for when a major infestation will occur, it can be difficult to control. However, since infestations tend to be more common in fields where corn is continually planted, crop rotation has shown to have effective results. 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 To control the tobacco wireworm with insecticides, Bifenthrin, clothianidin, and thiamethoxam proved to have effective control. Phorate, tefluthrin, and terbufos in granular form were also successful. Diazinon and parathion were effective when wireworm populations were not too significant. Be sure to carefully 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 insecticides. Granular insecticides should be applied at planting. This pest has developed a tolerance to chlorinated hydrocarbon and some other insecticides that are organophsphates. Latin / Alternative Tobacco Wireworm NamesSources |