Giant reed, Arundo donax L., is a large, bamboo-like plant native to the Mediterranean region. It has invaded several thousand hectares of the Rio Grande riparian habitat in Texas and Mexico. The United States Department of Agriculture-Agricultural Research Service (USDA-ARS) is investigating four herbivore insects as potential biological control agents for giant reed. One of the most important reasons for targeting this invasive weed is to reduce its impact on available water supplies, especially in the Rio Grande Basin. This study examined selected economic implications of this program for agricultural water users in the U.S. The research included (a) estimating the value of the water saved (to agricultural purposes) by reduction of giant reed, (b) benefit-cost analyses, (c) regional economic impact analyses, and (d) an estimate of the per-unit life-cycle cost of water saved during a 50-year planning horizon (2009 through 2058).

Positive results related to the benefit-cost ratio, economic impact analyses, and competitive results for the per-unit life-cycle cost of saving water are associated with the biological control project for giant reed. The benefit-cost ratio, calculated with normalized prices, indicates $4.38 of benefits for every dollar of public investment. According to 2009 results for the economic impact analyses, economic output is $22,000, value-added is $11,000, and no employment is supported by the water savings from giant reed. Additionally, the per-unit cost of water saved is $44.08, a value comparable to other projects designed to increase water supply for the region. These results indicate this program will have positive net economic implications for the U.S. and the Lower Rio Grande Valley of Texas.

Sorghum, Sorghum bicolor (L.) Moench, is important to the economies of Texas and the U.S. Sorghum midge, Stenodiplosis sorghicola (Coquillett), attacks flowering sorghum, causing substantial loss of grain every year. Sorghum midge-resistant genotypes are available for use in breeding programs to develop agronomically superior sorghum hybrids. Estimated yield loss caused by sorghum midge varied between 94.2 and 890.8 and 12.9 and 188.8 kg/ha if sorghum midgesusceptible and resistant hybrids, respectively, were grown. Yield saved by using a resistant hybrid was 48.1 (45.3 kg/ha) to 96.7% (702.0 kg/ha). Benefits accrued during a 25-year period were 66.7, 99.9, and 319.8 million (in 1984 constant dollar) at 1, 5, and 15% compounding/discounting rates, respectively. The corresponding accruable costs were $4.3, 6.7, and 23.4 million. Net present value was positive and cost-benefit ratio was less than one, indicating investment in developing a sorghum midge-resistant hybrid was profitable. Depending on the interest rate, a dollar invested in research and development of a sorghum midge-resistant hybrid would generate $13.6 to 15.7.

Timothy, Phleum pretense L., is an important forage crop in many western U.S. states. Thrips are an important pest of this crop. The effectiveness of field burning as an alternative management tactic for thrips is undocumented. Small-plot burn experiments were initiated with a hand-held torch in two fields in late winter 2007 and in one field on 5 March 2008. Thrips numbers assessed 2 weeks after burning. Grower-burned and nonburned fields were sampled post-burning for thrips on 20 March 2007 and 2008. In 2007, one experiment had relatively low overall abundance of thrips, and adults and larva were found only in nonburned plots. In the other 2007 experiment, more larvae were found in nonburned than burned plots, although adult numbers were similar. In 2008, the number of adults was greater in nonburned plots, while numbers of larvae were relatively low and were similar between burned and nonburned plots. There were no significant differences in thrips abundance between burned or nonburned grower fields during either year. Primarily brachypterous adults were found but both brachypterous adults and larva were found when sampling occurred later or in warmer areas. Timing of burning, in correlation with thrips phenology, was the most likely explanation for differences in population structure between years in burned plots. Population distributions were not aggregated over the spatial scales of these plot experiments. Burning was demonstrated as a possible short-term management tool, but other factors, in addition to burning, probably are important for regulating abundance in the long term.

Species, seasonal abundance, damage, control, and predaceous natural enemies of thrips (Thysanoptera: Thripidae) on cotton, Gossypium hirsutum L., were determined at two sites from 2005 to 2007 in the Lower Rio Grande Valley of Texas. Thrips can stunt growth and reduce yield potential. Seven species of thrips were found. When the cotton field was 0.5 km from commercial onion, Allium cepa L., the predominant species were western flower thrips, Frankliniella occidentalis (Pergande) (61.7%) and onion thrips, Thrips tabaci Lindeman (27.2%). A cotton field 50 km from a commercial onion-growing area was infested with western flower thrips (68.5%) and bean thrips, Caliothrips fasciatus (Pergande) (29.2%). At both fields, cotton seedlings from the cotyledon to 3-4-true leaf stages were most susceptible to onion thrips. Western flower thrips and bean thrips were found predominantly on 5- to 6-true-leaf stage and older cotton. Thrips were found in cotton at the beginning of the growing season and increased gradually in abundance, peaking in mid-May to late June. Predators on cotton were: minute pirate bugs, Orius spp.; lady beetles, Hippodamia spp.; green lacewing, Chrysopa rufilabris (Burmeister); bigeyed bugs, Geocoris spp.; spiders, Argiope spp., and syrphid flies, Syrphus spp. Orius spp. were the most abundant predators (69.5% on nontreated cotton). Heavy rainfall temporarily reduced abundance of thrips on cotton. The systemic insecticides thiamethoxam (Cruiser™) and imidacloprid (Gaucho Grande™) applied to seeds protected cotton from thrips for as long as 30 days after planting.

Effects of cotton, Gossypium hirsutum L.; green bean, Phaseolus vulgaris L.; and sweet potato, lpomoea batatas (L.) Lam.; on mortality and development of sweetpotato whitefly, Bemisia tabaci (Gennadius) biotype B; bandedwinged whitefly, Trialeurodes abutilonea (Haldeman); and greenhouse whitefly, T. vaporariorum (Westwood); and on the key biological parameters of an exotic parasitoid species, Eretmocerus mundus Mercet, and an indigenous parasitoid, Encarsia pergandiella Howard, were compared in the laboratory. Cotton was most suitable for sweetpotato whitefly, and bean was most suitable for greenhouse whitefly. No significant differences were found between these two whitefly species on sweet potato. Preimaginal mortality of sweetpotato whitefly on cotton was 35.2% versus 77.3% of greenhouse whitefly. Developmental time of sweetpotato whitefly was significantly shorter (17.5 days) than that of greenhouse whitefly (23.2 days). The mortality and developmental time of bandedwinged whitefly did not differ on the different host plants. Parasitism by Er. mundus was greatest in sweetpotato whitefly and least in greenhouse whitefly when both whiteflies were reared on cotton. Parasitism of bandedwinged whitefly was intermediate. Parasitism by En. pergandiella was significantly greater than that by Er. mundus attacking the same whitefly species reared on bean or cotton, except parasitism of sweetpotato whitefly. Emergence of Er. mundus was greatest from sweetpotato whitefly on cotton, and least for bandedwinged whitefly on bean. Emergence of En. pergandiella was significantly greater than that of Er. mundus among host plants and whitefly species except sweetpotato whitefly.

Pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae), is a major fruit pest of pecan, Carya illinoinensis (Wangenh.) K. Koch. The majority of economic damage results from larvae feeding on the kernel. Pecan fruit were collected at three sites to describe oviposition activity related to location on the fruit, cluster size, and determine the likelihood of multiple females ovipositing in the same fruit. Results indicated that oviposition was primarily at the distal (stigma) end of the fruit, although feeding punctures seemed to occur without respect to fruit location. Infestation of a fruit cluster rarely resulted in all fruit in the cluster being infested; in fact, one or two fruit were the most common infestation level, regardless of cluster size. Infestation by larvae typically occurred at greater frequency in larger clusters and less frequency in single fruit clusters than the infestation rate across all cluster sizes, suggesting that more fruit produced a greater concentration of volatile compounds attractive to females. Multiple punctures in the shuck were frequently observed, but multiple punctures of the testa were rare when infestation was moderate but increased when infestation was high. This indicated that feeding by adult weevils was not affected by earlier feeding, but deep penetration of the fruit leading to oviposition was inhibited by a previous penetration of the testa. In orchards with the majority of the crop infested, fruit were identified with larval development up to the third instar, combined with eggs. Evidence suggests an oviposition-marking pheromone produced by the host or female weevil deters other females from using the fruit for reproduction, but will not avert multiple oviposition episodes when non-infested fruit are sparse.

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), is the major vector of Xylella fastidiosa Wells et al., the causal agent of Pierce's disease of grapes, Vitis spp. More research on leafhopper stress response is possible as more genomic information becomes available. To gain information on the stress response of the glassy-winged sharpshooter, a cDNA library was constructed from adults and fifth instars, resulting in 5,906 expressed sequence tags (ESTs). After quality scoring, 4,445 sequences underwent assembly, which produced a set of 2,123 sequences that putatively represented distinct transcripts. BLASTX analysis identified four significant homology matches to heat shock proteins (HSP), which are the focus of this study. The overall importance and function of heat shock proteins lie in their ability to maintain protein integrity and activity during stressful conditions, such as extreme heat, cold, or drought. Phylogenetic analyses using these four heat shock protein sequences provided further support of transcript by the identification of specific motifs. This study shows that highly conserved genes such as heat shock proteins are a viable supplement to ribosomal DNA in elucidating phylogenetic relationships.

Stable flies, Stomoxys calcitrans L., are important pests of confined and pasture cattle. They have been reared in the laboratory to study their biology and to test new methods of control. Research on rearing modifications has concentrated on developing larval diets from materials locally abundant. Under current protocols, pupae form in the medium. Aggregations of pupae were located and removed, often with a considerable amount of extraneous material. Various methods have been developed to separate the pupae from waste material. We describe a method by which wandering larvae are enticed to leave the medium prior to pupariation. The larvae were attracted to a moist cloth on a shelf positioned at the end of the rearing pan. Almost 85% of the wandering larvae were collected on the shelf. This simplifies obtaining clean pupae and allows for collecting pupae of known age for experimental work. We also include data on the rate at which the larvae wandered onto the shelf under conditions we used in the laboratory.

A microassay was used to determine the activities of α- and β-esterases and acetyl Cholinesterase in larvae and adults of populations of Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae), in northeastern Mexico. Main collection sites were cemeteries and tire dumps. Three mechanisms of resistance were determined; however, elevated β-esterase activity was prominent, with frequencies greater than 92% in adult Asian tiger mosquitoes in three of the populations. Based on these results, we concluded that the mechanisms of resistance in the populations studied are caused mainly by esterase activity. This study can serve as a reference for future programs aimed at controlling this species.