Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2010
Publication Date: 8/1/2010
Citation: Snodgrass, G.L., Jackson, R.E., Abel, C.A., Perera, O.P. 2010. Utilization of Early Soybeans for Food and Reproduction by the Tarnished Plant Bug (Heteroptera: Miridae) in the Delta of Mississippi. Environmental Entomology. 39(4): 111-121 DOI: 10.1603/EN09379 Interpretive Summary: Soybean producers began growing maturity group IV soybeans extensively in the mid-South in the late 1990’s. These soybeans are planted in April, begin flowering in May, and fill pods in June and July. In 2007, soybean production in Mississippi was estimated at 587,000 ha of which 72% were planted before May 6. Their production along with increased production of corn has reduced cotton acreage from 471,000 ha in 2006 to 270,000 ha in 2007, and this trend has continued through 2009. Little information is available about soybeans serving as a host for the tarnished plant bug which is a serious pest of cotton in the mid-South. The present study was conducted to evaluate early soybeans as a tarnished plant bug host. Results from laboratory rearing studies and cage tests in the field showed that early soybeans were a marginal host for tarnished plant bugs. However, extensive sampling of commercially grown soybeans found numbers of plant bugs high enough to cause some damage to the soybeans. An evaluation of this possible damage was not conducted. The sampling of the commercial soybeans showed that plant bugs could produce one generation in the soybeans during the time the soybeans flowered. Tarnished plant bugs only utilize hosts for reproduction when they flower. Adults migrated from the fields when flowering ended during June and moved into wild hosts, group V soybeans, corn, or cotton which all flower in June. The early soybeans served as a very abundant host at a time in which only wild hosts were previously available. Reproduction of tarnished plant bugs in early soybeans is detrimental to cotton production since it increases numbers of adults in cultivated crops and wild hosts in June. They increase in numbers again on these hosts while the hosts flower, then adults migrate from them during July into cotton, their most abundant host that is flowering during July.
Technical Abstract: Commercially produced maturity group IV soybeans, Glycine max L., in bloom were sampled for tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), in May and June of 1999 (3 fields) and 2001 (18 fields). The adults and nymphs found in the fields both produced single population peaks in both years indicating a single new generation was produced in each year. The peak mean numbers of nymphs were 0.61 and 0.84 per drop cloth sample in 1999 and 2001, respectively. Adults peaked at 3.96 (1999) and 3.76 (2001) per sweep net sample (25 sweeps). Laboratory and field rearing tests on soybeans found very poor survival of nymphs on 16 different maturity group III (1), IV (4), V (9) and VI (2) varieties. A large cage (0.06 ha) field test found that the number of nymphs produced on 8 soybean varieties after mated adults were released into the cages was lower than could be expected on a good host. These results indicated that soybean was a marginal host for tarnished plant bugs. However, the numbers of adults and nymphs found in the commercially produced fields sampled in the study were high enough to cause feeding damage to the soybeans as they flowered. The nature of the damage and its possible economic importance were not determined. Reproduction of tarnished plant bugs in the commercially produced early soybean fields showed that the early soybeans provided tarnished plant bugs with a very abundant host at a time when only wild hosts were previously available. The role that early soybeans play in the population dynamics of the tarnished plant bug in the mid-South is discussed.