Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2006
Publication Date: 10/1/2007
Citation: Ni, X., Wilson, J.P., Rajewski, J.A., Buntin, G.D., Dweikat, I.M. 2007. Field screening of pearl millet for chinch bug (Heteroptera:Blissidae) resistance. Journal of Entomological Science. 42:467-480. Interpretive Summary: Pearl millet is grown as a forage, cover and grain crop in the arid and semi-arid regions worldwide. It has been studied in the U.S. in recent years as a poultry ration ingredient due to its nutritional quality and minimal processing costs. The chinch bugs and the false chinch bugs cause significant injury and loss of seedling stands in Georgia and other southeastern states of the U.S. The chinch bug could cause stunting, necrosis of leaf sheath, and high infestation would cause the death of seedlings by their sucking of plant sap underneath leaf sheath. This study examined 16 pearl millet inbred lines and experimental hybrids for chinch bug resistance by evaluating plant and insect injury on plants. Using a combined injury assessment method including four weekly stunting and necrosis ratings, tiller loss, and final crop stand loss, we identified three entries as the most resistant, and three entries as the most susceptible to chinch bug feeding, which would be valuable for the breeding program to develop new chinch bug-resistant germplasm.
Technical Abstract: The chinch bug, Blissus leucopterus leucopterus (Say) (Heteroptera: Blissidae), is the most important insect pest for pearl millet (Pennisetum glaucum L. R. Br.) production in the southeastern and central U.S. Chinch bug feeding causes stunting and leaf sheath necrosis of the young seedlings, and loss of crop stand in severe infestations. Sixteen germplasm entries (including hybrids and inbreds) of pearl millet were screened for chinch bug resistance on two planting dates. ‘Dove’ proso millet (Panicum miliaceum L.) was interplanted in two-row strips among experimental plots to attract adult chinch bugs and establish initial chinch bug infestations. The weekly samplings started when plants were at the 5-leaf stage. Use of a proso millet trap crop strip was effective for establishing chinch bug infestations for screening of pearl millet for chinch bug resistance in the field. Significant differences in adult and nymph numbers, stunting and necrosis ratings, percent tiller loss, crop stand loss, and chlorophyll content were recorded for the 16 pearl millet germplasm entries. Combining all injury evaluation parameters (i.e., stunting and necrosis ratings, percent tiller loss, and crop stand loss), we identified Tifgrain 102 had moderate level of chinch bug resistance. Entries 637 (i.e., 59668A x NM-5B), 648 (i.e., 02GH973 x Tift 454), and 653 (i.e., NM-5A1 x NM-7R1R5) were the most resistant, whereas entries 640 (i.e., Tift 99B), 641 (i.e., Tift 454), and 644 (i.e., 02F 289-1) were the most susceptible to chinch bug feeding. The study showed the combination of non-destructive visual ratings (i.e., stunting and necrosis ratings, tiller loss, and stand loss) and chlorophyll content could be used for evaluating chinch bug resistance in pearl millet.