Switchgrass (Panicum virgatum L.) has tremendous potential as a biomass and stock crop for cellulosic ethanol production or combustion as a solid fuel. A three-year study was conducted to assess insect and weed diversity in a perennial switchgrass crop in Florence, SC. Insects were sampled from 2007 to 2009, using pitfall traps and sweep-nets. Collected specimens were identified to family and classified by trophic groups, and the predominant species were identified. The diversity and density of weeds in the field during the establishment year (2007) were greater than the following years. The ratio of dry weight of switchgrass to weeds increased from 2.4 in January 2008 to 15.3 in January 2009. Insect diversity at the family level varied significantly across sampling dates only for sweep-net samples, with diversity peaks in May of each year. Diversity at the trophic-group level showed significant differences for predators in pitfall traps and for predators and herbivores in sweep-net samples across dates. Diversity of herbivores in pitfall traps tended to decrease over time. Draeculacephala sp., Melanoplus sp., and a species of Tettigoniidae were the predominant herbivores, while Solenopsis invicta Buren was the predominant predator. Assessing arthropod diversity in switchgrass is a first step in identifying potential pest and beneficial insects in this crop.

This paper reports on the EAG and behavioral responses of unmated females, unmated males, and mated females of Batocera horsfieldi (Hope) (Coleoptera: Cerambycidae) to ten plant volatiles. Seven volatiles tested from the host species Viburnum awabuki K., Betula luminifera H. Winkl, Juglans regia L., and Populus tomentosa Carr. were β-myrcene, (Z)-3-hexen-1-ol, nonanal, dichloromethyl ether, salicyaldehyde, 3-methylbutyric acid, and trichloroethylene. Three volatiles tested from non-host conifers were (1S)-(−)-β-pinene, (1R)-( )-α-pinene, and (1S)-(−)-α-pinene. The EAG responses of unmated B. horsfieldi females to these ten volatiles were tested at five concentrations (0.0001, 0.001, 0.01, 0.1, and 0.2 µL/µL). For eight of the volatiles, the EAG responses did not change significantly after their concentration was increased to 0.1 µL/µL. However, the maximum EAG response to 3-methylbutyric acid was at 0.0001 µL/µL and it decreased at higher concentrations. The EAG response to salicyaldehyde increased throughout the range of concentrations. The EAG response of mated females to salicyaldehyde at 0.1 µL/µL was significantly stronger than for unmated females or unmated males. EAG data showed that (1S)-(−)-β-pinene at 0.2 µL/µL had a strong repellent affect on unmated female and unmated male B. horsfieldi adults (P < 0.01). At 0.2 µL/µL, (Z)-3-hexen-1-ol had an attractive effect on unmated females (P < 0.05) and salicyaldehyde had an attractive effect on mated female B. horsfieldi adults (P < 0.05) in a Y-tube olfactometer. There was no significant difference in the repellent or attractive effects of dichloromethyl ether, 3-methylbutyric acid, or (1R)-( )-α-pinene at five concentrations to unmated female or male B. horsfieldi adults.

This study was conducted to determine the density, the incidence of parasitism, and the generalist predator assemblage of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), on orange jasmine plants [Murraya paniculata (L.) Jack] in the residential landscape of Miami-Dade County, Florida. Flush shoots (10 cm) were collected from ten orange jasmine hedges in each of the four communities (Doral, Coral Gables, Palmetto Bay, and Homestead). We did not detect any consistent pattern in the fluctuation of psyllid density over time in the four communities. The greatest densities of eggs (65.5 ± 36.3 eggs/shoot), early instars (first to third) (87.2 ± 47.8 nymphs/shoot), and late instars (fourth and fifth) (16.9 ± 9.3 nymphs/shoot) were detected on 24 May 2006 in Palmetto Bay (egg) and Doral (early and late instars). The density of adult psyllids remained below two individuals per flush shoot at all locations for the entire sampling period. There were no consistent correlations between environmental factors (temperature, relative humidity, precipitation, and wind speed) and the densities of nymphs and eggs. Percent parasitism by Tamarixia radiata (Waterston) averaged 18.5% in 2006, and no consistent patterns were observed among communities and sampling dates. Ladybeetles, syrphid flies, and spiders were the most common generalist predators observed on the psyllid-infested flush shoots.

To address inquiries from the general public and Florida mosquito control programs on the effectiveness of natural products to control resting adult mosquitoes on vegetation, we conducted a study that evaluated the toxicity of several commercially available products containing plant essential oils against female Aedes albopictus (Skuse) and Culex quinquefasciatus Say (Diptera: Culicidae) when applied to the leaves of a common Florida landscape shrub, the southern wax myrtle, Myrica cerifera L. (Myricaceae). The products tested were EcoExempt MC©, Misting System Concentrate©, Mosquito Barrier©, No-See-Um Organic Repellent©, and Orange Guard©. All products were applied at maximum label rates via a hand pump sprayer and compared with a commercial formulation of synergized pyrethrins, Riptide©, as a standard. Excised leaf bioassays revealed that the essential oil formulations provided less than 10% mortality to both mosquito species with essentially no residual activity beyond 24 h. Riptide provided significantly greater mortality, approximately 25% and 41%, at 24 h for Ae. albopictus and Cx. quinquefasciatus, respectively, but this product did not exhibit residual activity beyond 24 h on treated leaves. We conclude that vegetative surfaces treated with the above products containing essential oils would not prove sufficiently effective to control mosquitoes when compared with conventional pyrethroid insecticides labeled for the same purpose.

The Colorado potato beetle Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) in the northern part of the Xinjiang Uygur Autonomous Region has evolved resistance to several pyrethroid and carbamate insecticides. Biological control methods should be a major component of integrated pest management for L. Decemlineata. Spinosad and abamectin are two biopesticides that have unique mechanisms of action. In this study, the contact toxicities of spinosad and abamectin to L. Decemlineata fourth instars and adults were determined by topical applications to several field populations. The average LD₅₀ values of spinosad and abamectin for adults were 0.1275 and 0.0101 µg (a.i.) per individual, and for fourth instars they were 0.0181 and 0.0016 µg (a.i.) per individual, respectively. These data were among the lowest LD₅₀s ever estimated, which affirmed that the two biopesticides are useful for L. Decemlineata control in north Xinjiang. Susceptibilities to the two biopesticides varied slightly but significantly among tested field populations and the variations did not result from cross-resistance to conventional insecticides. Regarding stomach toxicities, the LC₅₀ values of spinosad applied to excised potato leaves for second instars, third instars, fourth instars, and adults were 0.2840, 0.4093, 1.2413, and 2.3783 mg/L (a.i.), respectively. The LC₅₀ values of abamectin for second instars, third instars, fourth instars, and adults were 0.0036, 0.0088, 0.0177, and 0.2591 mg/L (a.i.), respectively. The two biopesticides were most toxic to second instars, followed by third, then fourth instars, and they were least toxic to adults. These data suggested that the appropriate timing for spinosad or abamectin spraying is to early larval stages.