About the Tobacco Flea BeetleReproduction and Life Cycle The tobacco flea beetle will overwinter as an adult under dead leaves, litter, or dirt clods in, and around fields of host plants. They will especially overwinter directly in the fields of tobacco if plant stalks were not removed following harvest. When the weather starts to warm up, often in the middle of spring, this pest will travel to available host plants. They are strong fliers, and can find these emerging seedlings from the plants chemical cues that are emitted. The beetles will continue to feed for a couple of weeks. The females will lay their fertilized eggs during this time underneath tobacco plants in the ground. The eggs will take about 7 days to hatch into larvae. The larvae feed on stems and small roots of the host plants. They go through 3 instars, taking about 4 or 5 weeks; this stage of development does not typically cause a significant amount of damage to the plant. They form their pupae in the ground and will complete this stage in 4 to 7 days and then emerge as adults. This cycle continues for up to 4 generations annually until harvest hits, which is when the adults overwinter. Tobacco Flea Beetle Identification and HabitatIdentification The adult is a black beetle that tends to be very active, has a hard outer shell and is about 1.5mm in length. The wing covers have a striped appearance due to distinct, lengthwise punctures that run the entire length of the wing. They have black eyes and long antennae that have 12 sections. As an adult, this pest will jump similarly to that of a flea with its powerful back legs if disrupted. The eggs are tinier then a pinhead, white in colour, and are elongated with a pointed head. The larvae will reach to be about 4.5mm long when mature; they are white and worm-like. The head is brown and the body consists of 12 segments. They have a proleg at the rear and 3 sets of legs on the thorax. The pupa is also white, with its head bowed in a downward position. Habitat This pest is mainly a problem for seedlings, usually of tobacco plants; however, they will feed on a number of other plants as well. They can also damage adult plants, but the injury at this stage is not near as serious since the plant is often strong enough to recover. The beetles will chew round, little holes in the leaves that are referred to as “shot holes”. While the larvae mostly feed on the plants root system, it will only cause severe damage if they present themselves in large numbers. When the foliage of seedlings is fed on, the plants growth can be stunted and will sometimes die. Tobacco Flea Beetle Management and Control MethodsCultural Control This pest does not often cause a significant amount of damage; they typically must eat about 10 to 20 percent of the leaves on mature plants in order for the yield to be affected. However, treatment is warranted if seedlings are infested. “Trap crops” can be used to lure the tobacco flea beetles to an area away from your crops. Once your crop has been established, the “trap crop” can be killed or harvested. You can also plan to set up floating row covers to keep beetles from flying to those seedlings. Additionally, make sure you get rid of possible overwintering sites for the beetle, such as tobacco stalks in the field, or trash and litter lying near the field. Microtonus epitricis, a braconid wasp, can also keep their population suppressed. It is important to note that having satisfactory control is dependent on using an integrated management system that includes the use of cultural and chemical methods. Chemical Control For chemical control, insecticides that have carbaryl, bifenthrin, spinosad, or permethrin have been shown to have effective results. That being said, when applying insecticide to seedlings, reapplication often needs to occur for positive results to last. 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 it is important to irrigate sprayed area to increase the insect control. However, note that a large rainfall or irrigation soon after the application can reduce the concentration of insecticides. Another repellent is diatomaceous earth, which can be applied to the plants as a powder. Horticulture oils have also had some success. Latin / Alternative Tobacco Flea Beetle NamesSources http://bugguide.net/node/view/467219 http://www.ext.colostate.edu/pubs/insect/05592.html http://ipm.ncsu.edu/AG271/tobacco/tobacco_flea_beetle.html http://www.ipm.ucdavis.edu/PMG/r604300611.html |