|Nansen, Christian - Texas Agrilife Research|
|Stokes, Bryan - Texas Agrilife Research|
|James, Jacob - Texas Agrilife Research|
|Porter, Patrick - Texas Agrilife Research|
|Wheeler, Terry - Texas Agrilife Research|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2013
Publication Date: 4/1/2013
Citation: Nansen, C., Stokes, B., James, J., Porter, P., Wheeler, T., Meikle, W.G. 2013. Biological control agent of larger black flour beetles (Coleoptera: Tenebrionidae): A nuisance pest developing in cotton gin trash piles. Journal of Economic Entomology. 106 (2) 648:652. DOI: http://dx.doi.org/10.1603/EC12380.
Interpretive Summary: With cotton production, comes the production of leftover plant parts, called “gin trash”. Gin trash is largely harmless, but as it decays it is attacked by fungi, and beetles, mainly the larger black flour beetle, or LBFB, that arrive to eat the fungi. These LBFB can build up to very high numbers and are a nuisance pest to people living in the area. Control methods are needed. Chemical control is not very desirable because of risks of contamination. Biological control, as part of an integrated pest management program, may be one way to keep beetle numbers down. In this study, a number of experiments were conducted to see if entompathogenic nematodes,tiny worms that live in the soil, can help control LBFB. Experiments were conducted using containers of many different sizes, from petri dishes to Mason jars to 120 liter plastic containers. The objectives were to see whether the nematodes would attack the beetles, what factors, such as soil moisture, might be important to help nematodes, and what doses of nematodes might be needed. The researchers found that nematodes do attack the beetles, that soil moisture content is very important and nematodes also like an alternative food source (in case they cannot find any LBFB). The large scale experiment did show some nematode impact, but some containers probably dried out too much. That experiment will need to be re-done, with some changes. The conclusion is that using nematodes to control LBFB is promising, but more large-scale work needs to be done.
Technical Abstract: Larger black flour beetles (LBFB), Cynaeus angustus, feed on saprophytic fungi found in gin trash piles, and become nuisance pests in homes and businesses. We examined the dose-response of three entomopathogenic nematode species (Steinernema carpocapsae, S. feltiae, and Heterorhabditis bacteriophora) as control agents of LBFB under different soil moisture content conditions. Steinernema carpocapsae and S. feltiae were associated with higher LBFB mortality than H. bacteriophora. A second laboratory study showed that: 1) LBFB larvae are more susceptible to S. carpocapsae than adults, 2) soil moisture positively affected virulence of S. carpocapsae, and 3) presence of a corn meal and glycerine pellet increased S. carpocapsae virulence. In a Mason jar study over 154 days, S. carpocapsae had the highest impact on LBFB populations with soil moisture about 15% by weight, and S. carpocapsae were recovered in significant numbers 154 days after inoculation. In a study with large (120 L) experimental units containing soil and gin trash and monitored for 91 days, we showed that LBFB populations were significantly affected by nematode treatments. Data presented here support further research into applications of entomopathogenic nematodes underneath gin trash piles as a way to minimize risk of LBFB populations causing harm to nearby homes and businesses.