Effects of Burial and Soil Condition on Postharvest Mortality of Boll Weevils (Coleoptera: Curculionidae) in Fallen Cotton Fruit

Effects of soil condition and burial on boll weevil, Anthonomus grandis grandis Boheman, mortality in fallen cotton, Gossypium hirsutum L., fruit were assessed in this study. During hot weather immediately after summer harvest operations in the Lower Rio Grande Valley of Texas, burial of infested fruit in conventionally tilled field plots permitted significantly greater survival of weevils than in no-tillage plots. Burial of infested squares protected developing weevils from heat and desiccation that cause high mortality on the soil surface during and after harvest in midsummer and late summer. A laboratory assay showed that burial of infested squares resulted in significantly greater weevil mortality in wet than in dry sandy or clay soils. Significantly fewer weevils rose to the soil surface after burial of infested bolls during winter compared with bolls set on the soil surface, a likely result of wetting by winter rainfall. A combination of leaving infested fruit exposed to heat before the onset of cooler winter temperatures and burial by tillage when temperatures begin to cool might be an important tactic for reducing populations of boll weevils that overwinter in cotton fields

Effects of Burial and Soil Condition on Postharvest Mortality of Boll Weevils (Coleoptera: Curculionidae) in Fallen Cotton Fruit

Effects of soil condition and burial on boll weevil, Anthonomus grandis grandis Boheman, mortality in fallen cotton, Gossypium hirsutum L., fruit were assessed in this study. During hot weather immediately after summer harvest operations in the Lower Rio Grande Valley of Texas, burial of infested fruit in conventionally tilled field plots permitted significantly greater survival of weevils than in no-tillage plots. Burial of infested squares protected developing weevils from heat and desiccation that cause high mortality on the soil surface during and after harvest in midsummer and late summer. A laboratory assay showed that burial of infested squares resulted in significantly greater weevil mortality in wet than in dry sandy or clay soils. Significantly fewer weevils rose to the soil surface after burial of infested bolls during winter compared with bolls set on the soil surface, a likely result of wetting by winter rainfall. A combination of leaving infested fruit exposed to heat before the onset of cooler winter temperatures and burial by tillage when temperatures begin to cool might be an important tactic for reducing populations of boll weevils that overwinter in cotton fields

Mitigating Predatory Ants Promotes Establishment of Biological Control of Arundo by Arundo Scale in the Cattle Fever Tick Quarantine Zone

Ant collection, identification, and control experiments were conducted to improve the establishment of the arundo scale, Rhizaspidiotus donacis, a biological control agent of Arundo donax, an invasive weed in the riparian habitats along the Rio Grande in Texas. Observational studies indicated R. donacis immatures are preyed upon by a variety of predator insects, especially ants. A survey of the principle ant species was made at sites along the Rio Grande with Arundo donax to help direct biological control strategies. We conclude that uses of ant baits can effectively control the common ant species found in these habitats and improve the establishment of R. donacis

Spatio-temporal distribution of Anthonomus grandis grandis Boh. in tropical cotton fields.

The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is considered to be the most harmful cotton, Gossypium hirsutum L., pest throughout subtropical, and tropical regions of the western hemisphere.1,2 Boll weevil damages cotton by feeding upon and laying eggs inside its reproductive structures, where hatched larvae feed and pupate,3,4 causing abscission or reduction of fiber quality,3,5,6 and economic losses of up to US$74 million per year.7 Boll weevil chemical control interventions are based on economic thresholds obtained by sampling the plants and for adult boll weevils captured in pheromone-baited traps.3,8,9 In order to develop an accurate monitoring and management program, estimates of population density are essential.10,11 Biotic and abiotic factors affect dynamics and within-field distribution (aggregated, random or uniform patterns) of insect populations.10,12 Knowing a pest's distribution within a field can help to: (1) develop site-specific sampling and control efforts; (2) predict pest movement; (3) improve insecticide-resistance management; (4) conserve biological control agents by precision targeting sprays for the infested areas; and (5) reduce the economic, social and environmental costs associated with pest control.10,11,13 The spatial distribution of boll weevils has been investigated using mean?variance relationships4,14 without considering within-field spatial density distribution, or has been based on pheromone-baited trap captures.15 The most accurate approach is the use of geostatistics because the position of the samples in space is accounted for.16 Recent work reported that geostatistics is of particular interest for pest management because it allows inferences about the minimum inter-sample distance needed to obtain independent estimations and indicates patterns of distribution and colonization of an organism, all of which are crucial for the development of effective sampling programs.11,13 The purpose of this study was to investigate the spatial dynamics of A. grandis grandis on cotton by determining within-field distribution of adults and infested reproductive structures (having feeding and/or oviposition punctures)

Breeding productivity, nest-site selection and conservation needs of the endemic Turkestan Ground-jay Podoces panderi

The Turkestan Ground-jay Podoces panderi, a corvid endemic to the deserts of Central Asia, is both understudied and under-protected. Using standardised nest-monitoring protocols and nest cameras, we estimated its breeding productivity for the first time as 0.586 fledglings per nesting attempt (inter-quartile range, IQR 0.413‒0.734), strongly constrained by a diverse set of predator species (accounting for 88% of failures), supporting the broad pattern that a wide spectrum of nest predators operate in arid environments. The probability of nest success for the 35 days from the start of incubation to fledging was low, 0.186 ± 0.06 se (N = 37), with no influence of season date, nest height or nest shrub species. However, pervasive shrub harvest severely limited availability of taller shrubs for nest-site selection, and thus our ability to detect any effect of height on nest survival. Mean clutch size was 4.8 ± 0.8 sd while hatching probability of an egg from a clutch surviving incubation was 0.800 ± 0.050 se and fledging probability was 0.824 ± 0.093 se for individual chicks in successful nests (i.e. that fledged one or more chicks). Two shrub genera, saxaul Haloxylon spp. and Calligonum spp., were used for nesting more frequently than expected (χ152 = 784.02, P < 0.001), highlighting their importance to breeding habitat suitability. This near-sole reliance on these taller shrub genera, both targeted for illegal cutting, indicates that habitat degradation may lead to increased predation and declines in productivity. Habitat conservation is, therefore, likely to be the most important management strategy for the species and other components of desert systems, as management of so diverse a set of nest predators would be both impractical and inappropriate

What Works in Conservation 2018

This book provides an assessment of the effectiveness of 1277 conservation interventions based on summarized scientific evidence. The 2018 edition contains new chapters covering practical global conservation of primates, peatlands, shrublands and heathlands, management of captive animals as well as an extended chapter on control of freshwater invasive species. Other chapters cover global conservation of amphibians, bats, birds and forests, conservation of European farmland biodiversity and some aspects of enhancing natural pest control, enhancing soil fertility and control of freshwater invasive species. It contains key results from the summarized evidence for each conservation intervention and an assessment of the effectiveness of each by international expert panels. The accompanying website www.conservationevidence.com describes each of the studies individually, and provides full references