John L. Capinera

Dispersal of first-instar gypsy moth larvae in relation to population quality

SummaryField studies of dispersal by first instar gypsy moth larvae indicate that almost all larvae undergo an initial dispersal episode. However, in laboratory studies large larvae (from large eggs) disperse more frequently than small larvae (from small eggs) in the presence of favored food. Large larvae may be better adapted for dispersal. When larvae encounter unacceptable food or are denied food, larvae disperse more frequently and dispersal by small larvae is nearly as frequent as dispersal by large larvae. Factors affecting egg size may contribute to shifts in dispersal patterns of gypsy moth larvae and distribution of populations.

Relationships between insect pests and weeds: an evolutionary perspective

Abstract Weeds are an important plant resource for insects, although feeding by insects on weeds can have both positive and negative effects on crop productivity. Weeds also indirectly affect crops via their influence on beneficial insects, and by harboring plant and insect diseases. Weeds may affect the ability of dispersing insects to locate crop plants. The host relationship between insects and plants is highly variable, ranging from very specialized to generalized feeding behaviors. Despite the myriad interactions of weeds and insects, many aspects of the relationship are predictable. Most insects, including crop pests, are specialists, and preadapted to feed only on some plants, often within a single plant family. Even polyphagous insects often have a distinct preference hierarchy, feeding more widely only when preferred hosts are unavailable. Use of plants by insects is a dynamic interaction, with characteristics of the insect (e.g., mandible structure) and the plant (e.g., allelochemicals) affecting feeding behavior. Thus, weeds that are closely related to crops are particularly important in harboring insects that attack those crops. Crop production practices should seek to sever the taxonomic association between the crop and the weeds found within the crop, and nearby, by eliminating weeds related to the crop. This will make it less likely that insects will move easily from weed to crop plants, that damaging population densities of insects will develop in the field, and that insect vectors that harbor plant diseases will be harbored in the field. Particularly important integrated pest management practices include crop rotation, reduced use of chemical herbicides, and management of weeds in noncultivated areas.

Attraction of the redbay ambrosia beetle, Xyleborus glabratus, to avocado, lychee, and essential oil lures.

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is an exotic wood-boring insect that vectors the mycopathogen responsible for laurel wilt, a lethal vascular disease of trees in the Lauraceae. High mortality has occurred in native Persea species in the southeastern U.S., and the vector-pathogen complex poses an imminent threat to the production of commercial avocado, P. americana, in south Florida. There is a critical need for effective attractants to detect, monitor, and control this invasive pest. This study combined field tests and laboratory bioassays to evaluate the response of female X. glabratus to host-based volatiles from wood of avocado (cultivars of West Indian, Guatemalan, and Mexican races); from wood of lychee (Litchi chinensis, a presumed non-host that is high in the sesquiterpene α-copaene, a putative attractant); and to commercial lures containing manuka and phoebe oils, two reported attractive baits. Volatile collections and GC-MS analyses were performed to quantify the sesquiterpene content of test substrates. In the field, traps baited with lychee wood captured more beetles than those with wood from avocado cultivars; traps baited with phoebe oil lures captured more beetles than those with manuka oil lures (the current monitoring tool). In field and laboratory tests, X. glabratus did not show a preference among avocado races in either attraction or host acceptance (initiation of boring). In choice tests, lychee was more attractive than avocado initially, but a higher percentage of beetles bored into avocado, suggesting that lychee emits more powerful olfactory/visual cues, but that avocado contains more of the secondary cues necessary for host recognition. Emissions of α-copaene, β-caryophyllene, and α-humulene were correlated with field captures, and lychee wood may be a source of additional semiochemicals for X. glabratus.

LOCAL DIFFERENCES IN HOST USE BY TWO POPULATIONS OF THE COLORADO POTATO BEETLE

Local differences in performance on three host species (Solanum sarra- choides, S. rostratum, potato (S. tuberosum)) were demonstrated for two nonagricultural populations of Colorado potato beetle. Populations from north-central and northeastern Colorado showed differential larval growth rate, survival, size, and tendency to diapause. Statistically significant host x population interactions indicated that these differences were host-species dependent. Further analysis suggested that the two populations were most successful on the locally abundant and annually predictable host species of their respective community. Population differences in performance were pronounced on one wild host species (S. sarrachoides); performance was similar on the other host species. Extent of host specificity was related to composition of the flora. The population that was exposed to all three host species in the field showed high rates of survival on all hosts; there was no indication that beetles from this population showed major trade-offs in performance among hosts. The second population showed highly reduced survival and growth on the wild host species that is absent from its immediate range. Implications of these results for addressing questions about the beetles original host shift to potato are discussed. Our results, in particular the success of these nonpest populations on potato, suggest that no major phys- iological changes in performance were necessary in the beetle for colonization of potato.

Integrated Pest Management on Rangeland: A Shortgrass Prairie Perspective

Integrated pest management on rangeland :a shortgrass prairie perspective , Integrated pest management on rangeland :a shortgrass prairie perspective , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Forensically important calliphoridae (diptera) associated with pig carrion in rural north-central Florida.

Abstract A study to determine the relative abundance and seasonality of forensically important blow flies (Diptera: Calliphoridae) in rural north-central Florida was conducted using pig carcasses (Sus scrofa L.) as models for human bodies. Seven species of Calliphoridae were collected: Lucilia coeruleiviridis (=Phaenicia) (Macquart), Cochliomyia macellaria (F.), Chrysomya rufifaces (Macquart), Phormia regina (Meigen), Chrysomya megacephala (F.), and a few specimens of Calliphora livida Hall, and Calliphora vicina Robineau-Desvoidy. Species composition in aerial collections of adult flies, preserved larval collections, and samples of larvae reared to the adult stage were all highly correlated. Relative abundance of the species found was significantly different, with L. coeruleiviridis the most abundant species year-round. The relative abundance of the collected species varied significantly by day of decomposition and by season, with significant interactions between season and day, season and species, and day and species. L. coeruleiviridis, C. macellaria, C. rufifaces, and P. regina were found during the entire year, two C. vicina specimens and 11 C. livida specimens were collected from December to March, whereas C. megacephala was collected only from June through September.

Control of black cutworm, Agrotis ipsilon (Lepidoptera: Noctuidae), with entomogenous nematodes (Nematoda: Steinernematidae, Heterorhabditidae)

Various species and strains of entomophagous nematodes were assessed in the laboratory for their potential to infect black cutworm larvae, Agrotis ipsilon: Steinernema feltiae (= Neoaplectana carpocapsae) strains Mexican and Kapow, S. bibionis and Heterorhabditis heliothidis. Based on LD50 values, rates of mortality, and storage considerations, S. feltiae Mexican strain was chosen for additional evaluation. When incorporated into wheat-bran pellets and calcium alginate capsules, nematode dauerlarvae were able to escape and cause infection of cutworms, but wheatbran pellets allowed more rapid escape. Cutworms consumed wheat-bran pellets as readily as corn seedlings, but more readily than calcium alginate capsules. Addition of wheat bran to calcium alginate capsules did not enhance consumption by cutworms. Field studies suggested no value of wheat-bran bait formulation, relative to aqueous suspension, for delivering nematodes. Significant reduction in corn seedling damage by cutworms in plots inoculated with aqueous suspension of dauerlarvae was demonstrated. Application of nematodes at rates of about 5 × 105/m2 provided over 50% reduction in plant damage in some treatments.

A trail pheromone from silk produced by larvae of the range caterpillarHemileuca oliviae (Lepidoptera: Saturniidae) and observations on aggregation behavior

Methylene chloride-extractable chemical(s) from range caterpillar larval silk facilitates trail-following and aggregation by early-instar larvae, but late-instar larvae are less responsive to the pheromone. Larval aggregation does not reduce water loss when larvae are exposed to low humidity, nor does aggregation prevent predation by the antFormica neoclara Emery. Grouped larvae gain weight and complete early stadia more rapidly as compared to solitary larvae. Aggregation may provide increased visibility to herbivores and increase the impact of urticating spines, thereby decreasing inadvertant predation.

Effect of Trap Size, Trap Height and Age of Lure on Sampling Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), and its Flight Periodicity and Seasonality

ABSTRACT Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) is a non-native pest that transmits the causal pathogen of laurel wilt disease to plants belonging to the Lauraceae. To improve the current monitoring and survey techniques of X. glabratus, various trapping and flight behavior studies were conducted in natural areas with host species in Alachua County, Florida. Daylight flight rhythm studied at Austin Cary Memorial Forest twice in Sep 2010 using sticky traps baited with manuka lures showed that X. glabratus flies mostly between 1600 and 1800 h daylight saving time. Flight height of the beetle was determined in a trapping study using ladder-like traps. The largest number of beetles was trapped at heights of 35–100 cm above the ground. Seasonality of X. glabratus was studied in Florida from Mar 2010–Dec 2011. Three peaks of trap catches occurred during Apr 2010, Oct 2010 and Mar 2011. To find the optimal Lindgren funnel trap design for X. glabratus, a study was conducted using 4, 8, 12 and 16 funnels per trap. Funnel traps with 8, 12, 16 funnels per trap captured similar numbers of X. glabratus, but significantly more than with 4 funnels per trap. The effect of aging of manuka lures was studied at 2 different sites in Alachua County, Florida. New manuka lures trapped significantly more X. glabratus than lures aged 2, 4 and 6 wk. Trap color, whether black, white, blue, yellow, red or transparent, had no significant influence on the number of X. glabratus trapped.

Biochemistry and ultrastructure of iridescent virus type 29

Abstract Physical and chemical parameters of iridescent virus type 29, isolated from the mealworm, Tenebrio molitor, have been analyzed. The icosahedral capsid is 130–135 nm in diameter and is surrounded by a fringe of coarse filaments. The virus has a buoyant density in CsCl of 1.31 g cm−3 and contains 20 to 25 structural proteins as analyzed by isoelectric focusing and SDS-polyacrylamide gel electrophoresis. The DNA has a buoyant density in CsCl of 1.6874 g cm−3 indicating a G + C content of approximately 28%. The lipid components of this virus differ from those of the host cell; the virus contains about 80% cardiolipin and 20% phosphatidyl choline.