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The cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae) is an economically important insect pest of cotton in the United States. However, reports of cotton fleahopper infestation and its management in cotton fields are restricted primarily to Texas, Oklahoma, and Arkansas. The objective of this study was to understand the genetic diversity of cotton fleahopper populations infesting cotton in the cotton-growing areas of the United States. Amplified fragment length polymorphism markers were used to detect genetic diversity and to characterize geographic genotypes across the distribution of the cotton fleahopper in the United States. We used 172 individuals and 559 amplified fragment length polymorphism loci in this study and found significant, but low, level of genetic differentiation among geographic populations (FST = 0.02; P < 0.0001). Molecular fingerprints of cotton fleahopper populations were partitioned into three broad regional genetic populations with a western, central, and eastern distribution. The western (Arizona) and eastern (Florida, Georgia, South Carolina, and North Carolina) populations are genetically distinct, whereas the central (Texas, Oklahoma, Arkansas, Mississippi, Louisiana, and Alabama) population represents an admixed population, which include both western and eastern populations. These results suggest considerable gene flow among the populations within regions but restricted gene flow among populations from eastern and western region. [ABSTRACT FROM AUTHOR]

Several phytophagous insects exhibit distinct preference for their host plants. In widely distributed generalist insects, host preference can be influenced by geographic variation in host plant distribution and abundance as well as by prior experience. We have studied host preference of the cotton fleahopper, Pseudatomoscelis seriatus (Reuter), a pest of cotton in Texas and other neighboring states, by measuring olfactory orientation to horsemint (Monarda punctata L.) and cotton (Gossypium hirsutum L.). Horsemint is one of the primary, native, wild hosts of cotton fleahopper during late-spring and early summer in Texas, and it is commonly believed to be the main source of this pest in cotton. Although the abundance of horsemint, and therefore the fleahopper exposure to it, varies geographically, cotton fleahopper's preference for this native host-plant is maintained across two ecoregions in Texas, TX High Plains (Lubbock area) and Brazos Valley (College Station area). Similarly, preference for horsemint was retained regardless of prior experience with cotton throughout all the life stages of the insect. This fixed preference of cotton fleahopper to horsemint could be because of their ancestral insect-plant interaction, better fitness of cotton fleahopper on horsemint, and relatively low abundance of horsemint compared with cotton. Information gained from this study could be used to implement cultural control practices such as trap cropping, to develop attractants to monitor this pest, or both. [ABSTRACT FROM AUTHOR]

Previous studies suggest grain sorghum, Sorghum bicolor (L.) Moench, acts as an early-season predator source for nearby cotton, Gossypium hirsutum L., in areas where their growing seasons overlap. However, few data exist on predator movement in this system, and proposed causes of movement have not been tested. Field studies in 2001 and 200'2 addressed both issues. Predator marking with rubidium was employed to measure predator movement between equal-sized areas of cotton and grain sorghum at three stages of grain sorghum phenology. Concurrent manipulative experiments in field cages tested for effects of phenology and aphid levels on movement by Hippodamia convergens Guérin-Méneville, a common predator in this system. Results from 2001 showed cotton gained 2.7 predators for every one lost to adjacent grain sorghum but that the collective movement of predators was similar among the three periods examined. The coccinellids H. convergens and Scymnus loweii Mulsant moved preferentially into cotton and seemed responsible for the overall pattern of predator movement between crops. For predators moving from grain sorghum into cotton, estimated rates of dispersal (15.8‐19.9 m/d) were found to be similar among all taxa studied. Cage experiments suggested both crop phenology and abundance of aphid prey in cotton and grain sorghum cause predator movement, but only the effect of phenology was consistent between years. These results support the idea that grain sorghum is a source of predators during cotton's early growth stages and suggest that grain sorghum may continue to contribute to natural enemy populations during later stages of cotton growth. [ABSTRACT FROM AUTHOR]

A prey-specific gut content enzyme-linked immunosorbent assay (ELISA) was used to identify predation of eggs of bollworm, Helicoverpa zea (Boddie), by Orius spp. in commercial cotton fields in Texas. Degradation of the egg protein began immediately after O. insidiosus fed on an egg. However, the protein antigen was detectable in the predator for approximately 10 h after feeding. The antigen retention time provided a conservative estimate of predation and insured that when predation was detected it occurred on the day predators were collected. The percentage of individual of Orius spp. that was positive by ELISA for the egg antigen varied throughout each growing season. The highest frequency of positive responses occurred before cotton bloom and after peak bloom. [ABSTRACT FROM AUTHOR]

The population dynamics of the bollworm, Helicoverpa zea (Boddie), and its associated natural enemies were studied in insecticide-free, commercial, short-season cotton fields from 1991 to 1995 in the southern Blacklands of Texas. Bollworm had one discernable generation per season in cotton. Partial ecological life tables constructed for each annual generation indicated that 71–95% mortality could be consistently expected in the egg and first-instar life stages. Intrageneration mortality ranged from 93 to 99%. Unexplained mortality was the leading cause of mortality in 1991–1993, but not in 1994 and 1995 when predation due to Orius spp. was partitioned. Unexplained mortality included abiotic as well as biotic factors. Parasite activity was consistently low. Egg parasitization by Trichogramma spp. averaged 3.4%. Larval parasitization rarely exceeded 5% and no larval parasitization was found in 1993. Microplitis croceipes (Cresson) was the most common larval parasite collected. Predation of bollworm eggs by Orius insidiosus (Say), the numerically dominant predator in the system, was estimated using ELISA in 1994 and 1995. O. insidiosus was the most important mortality factor when measured consuming 84 and 71% of the eggs in 1994 and 1995, respectively. [ABSTRACT FROM PUBLISHER]