Abstract. Empirical protocols for assessing the suitability of prey for aphidophagous coccinellids are examined and a modified scheme of categorization is presented. It is argued that prey suitability should be assessed independently for larval development and adult reproduction because of potentially divergent nutritional requirements between these life stages. A scheme is proposed for assessing prey suitability for larval development using conspecific eggs as a reference diet against which diets of various prey types can be compared both within and among coccinellid species. Among suitable prey (those that support ca. 100% survival of larvae to the adult stage), those that promote faster development and yield larger adults relative to a conspecific egg diet are considered "optimal" for larvae. Prey that yield viable adults with similar or reduced adult weight after a similar or extended period of development relative to a diet of conspecific eggs are classified as "adequate". Prey are "marginal" if they support the survival of some larvae, but significantly less than 100%. Supplementary water should be provided with any non-aphid diet (e.g. pollen and alternative sources of animal protein) given the potential for food-specific diet-drought stress interactions. For adults, suitable prey are classified as "adequate" if they support the production of viable eggs when fed as a monotypic diet, or "marginal" if they merely prolong adult life relative to a water source. Prey that comprise an optimal or adequate diet for both larval development and adult reproduction are termed "complete" and these can be indexed for relative suitability according to derived estimates of rm. Potential sources of error in diet evaluation studies are identified and discussed.

Triticum mosaic virus (TriMV) is a newly discovered virus found infecting wheat (Triticum aestivum) in Kansas. This study was conducted to determine if the wheat curl mite (WCM, Aceria tosichella) and the bird cherry oat aphid (Rhopalosiphum padi) could transmit TriMV. Using different sources of WCM and two different isolates of TriMV, we were able to show the WCM is the vector of TriMV. Field analysis by enzyme-linked immunosorbent assay (ELISA) demonstrated natural infection patterns of wheat infected with TriMV, Wheat streak mosaic virus (WSMV), or both TriMV and WSMV, putatively infected by viruliferous WCM from a volunteer source growing adjacent to the wheat. Moreover, by single WCM transfers using WCM obtained from different wheat plants naturally infected with TriMV and WSMV and naturally infested with WCM, we showed that these WCM also transmitted TriMV only to wheat or transmitted both TriMV and WSMV to wheat. The infection rates of wheat with TriMV only using WCM transmission was low in both laboratory and field analyses. However, field analyses by ELISA showed that levels of infection of wheat by both TriMV and WSMV were high. No transmission of TriMV to wheat by R. padi occurred in our studies.

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Two ladybeetles, Cycloneda sanguinea (L.) and Harmonia axyridis Pallas, were exposed to leaf residues and topical applications of six insecticide formulations commonly used in citrus production in Florida. Exposure of larvae to leaf residues of chlorpyrifos corresponding to 1/100th the recommended field rate caused 55 and 73 percent mortality to larvae of C. sanguinea and H. axyridis, respectively. Cycloneda sanguinea was more sensitive than H. axyridis to all other materials tested. Both fenpropathrin and ethion plus petroleum oil caused significant mortality of larvae of both species as a leaf residue at the field rate and of C. sanguinea larvae at 1/10th the field rate. Sublethal doses of ethion delayed larval development in both species. Imidacloprid was toxic to larvae of both species as a leaf residue at the recommended rate and at 1/10th the recommended rate following topical application. Topical application of imidacloprid at the recommended rate killed 84.6% of adult C. sanguinea, whereas H. axyridis adults were unaffected. Adult beetles survived topical applications of chlorpyrifos, ethion + petroleum oil, and fenpropathrin at concentrations that were lethal to larvae. Esteem® (Valent USA Corp., Walnut Creek, CA) and Spinosad® (Dow Agrosciences, Indianapolis, IN) were relatively benign but did cause 38% and 28% mortality, respectively, of C. sanguinea larvae in topical assays. Fenpropathrin and Spinosad demonstrated repellency to adults of C. sanguinea, but not to adults of H. axyridis. The generally greater sensitivity of C. sanguinea to insecticides may represent a selective disadvantage for this native species in the citrus ecosystem relative the introduced H. axyridis.

Sugarcane stem borers of the genus of Diatraea (Lepidoptera: Crambidae) form a species complex that causes serious economic losses to sugarcane production in the Cauca River Valley and other regions of Colombia. Two primary species, Diatraea saccharalis (F.) and D. indigenella Dyar and Heinrich, have been effectively managed for more than 4 decades through augmentative releases of the tachinid flies Lydella minense (Townsend) and Billaea claripalpis (Wulp) (Diptera: Tachinidae) and the egg parasitoid Trichogramma exiguum Pinto & Platner (Hymenoptera: Trichogrammatidae). Here we review the current pest status of Diatraea species, damage assessment protocols, management tactics, and the environmental factors and cultural practices that can affect biological control outcomes. Recent changes in the cultivars grown have the potential to increase pest populations and diminish biological control efficacy. Additionally, recent outbreaks of new Diatraea species may further increase overall pest pressure. Thus, there is a need to develop supplementary tactics for the management of these pests that will be compatible with biological control, as well as more reliable protocols for assessing host plant resistance against the increase in infestation intensity.

A series of compounds representing four major pesticide groups were tested for toxicity to beneficial insects representing four different insect orders: Coleoptera (Coccinellidae), Hemiptera (Anthocoridae), Hymenoptera (Aphelinidae), and Neuroptera (Chrysopidae). These materials included organophosphates (methidathion, esfenvalerate and phosmet), carbamates (carbofuran, methomyl and carbaryl), pyrethroids (bifenthrin, fenpropathrin, zeta-cypermethrin, cyfluthrin and permethrin) and the oxadiazine indoxacarb. Toxicity to coccinellid and lacewing species was assessed by treating 1st instar larvae with the recommended field rate of commercial products, and two 10 fold dilutions of these materials, in topical spray applications. Adult Aphytis melinus Debach and 2nd instar Orius insidiosus (Say) were exposed to leaf residues of the same concentrations for 24 h. ANOVA performed on composite survival indices derived from these data resolved significant differences among materials with respect to their overall toxicity to beneficial insects. Cyfluthrin, fenpropathrin and zeta-cypermethrin all increased the developmental time of the lacewing and one or more coccinellid species for larvae that survived topical applications. Bifenthrin increased developmental time for two coccinellid species and decreased it in a third. Indoxacarb (Avaunt® WG, DuPont Corp.) ranked highest overall for safety to beneficial insects, largely because of its low dermal toxicity to all species tested. Zeta-cypermethrin (Super Fury®, FMC Corporation) received the second best safety rating, largely because of its low toxicity as a leaf residue to A. melinus and O. insidiosus. Phosmet (Imidan® 70W, Gowan Co.) and methidathion (Supracide® 25W, Gowan Co.) ranked high for safety to coccinellid species, but compounds currently recommended for use in citrus such as fenpropathrin (Danitol® 2.4EC, Sumimoto Chem. Co.) and carbaryl (Sevin® XLR EC, Rhone Poulenc Ag. Co.) ranked very low for IPM-compatibility based on their relatively high toxicity to all species tested.FRfield rate

Laboratory experiments examined interspecific interactions between larvae of three coccinellid species, Curinus coeruleus Mulsant (Chilocorinae), Harmonia axyridis Pallas and Olla v-nigrum (Mulsant) (Coccinellinae), and between these and larvae of the green lacewing, Chrysoperla rufilabris (Burmeister). Larvae of C. coeruleus, although defended on their dorsal surface with long spines, had the smallest mandibles, were the slowest-moving, and the least successful in interspecific larval combat. The long spines of third instar C. coeruleusappeared to reduce their palatability as food to H. axyridis and O. v-nigrum larvae in choice tests with dead larvae, but were not an effective defence against these species in Petri dish arenas. Larvae of O. v-nigrum had a smooth dorsal surface, were intermediate in terms of mandible size, but were the fastest moving, a trait that benefited their survival in intraguild combat. Larvae of H. axyridis were intermediate with respect to dorsal spines and speed of movement, but had the largest mandibles. This species was the most effective intraguild combatant among the coccinellids and the only one to successfully compete against C. rufilabris larvae of similar age. The speed, manoeuverability and long mandibles of C. rufilabris enabled them to impale coccinellid larvae at a relatively safe distance. The spines of C. coeruleus larvae impeded laterally oriented attacks by C. rufilabris, but did not provide sustained protection from repeated attacks. Success in these interactions appeared largely a function of offensive weaponry (mandible size and morphology) and speed of movement, although the role of dorsal spines as defensive structures was not ruled out. Rates of larval cannibalism were highest for C. rufilabris and largely mirrored the level of aggression observed in interspecific combat for each species.

Two fruit fly baits, Nu-Lure ® /malathion and GF-120 (Spinosad ® ) were evaluated in the laboratory for non-target impacts on beneficial insects. Nu-Lure/malathion proved attractive and toxic to adults and larvae of the coccinellid species, Curinus coeruleus Mulsant, Cycloneda sanguinea L. and Harmonia axyridis Pallas, a lacewing species, Chrysoperla rufilabris Burmeister. The coccinellids Olla v-nigrum Mulsant, Scymnus sp. and nymphs of the insidious flower bug, Orius insidiosus (Say) did not succumb to Nu-Lure baits, even in no-choice situations. Nu-Lure was also attractive and lethal to adults of two aphidophagous flies; Leucopis sp. and the syrphid fly Pseudodorus clavatus (F.). Both Nu-Lure and GF-120 caused significant mortality to the parasitoid wasps, Aphytis melinus De Bach and Lysiphlebus testaceipes Cresson, within 24 h of exposure. However, GF-120 caused no significant mortality to any coccinellid in either choice or no-choice situations, despite considerable consumption of baits. Adults of P. clavatus tended to avoid GF-120, although mortality was significant in no-choice tests. Although larvae and adults of the lacewing C. rufilabris consumed GF-120, mortality was delayed; adults died 48 -96 h post-exposure and those exposed as larvae died two weeks later in the pupal stage. The Nu-Lure bait did not appear palatable to any of the insects, but the high concentration of malathion (195,000 ppm) caused rapid mortality to susceptible insects. Nu-Lure bait without malathion also caused significant mortality to flies and lacewings in cage trials. Although GF-120 bait appeared more benign overall, further research efforts are warranted to increase its selectivity for target fly species and reduce its attractiveness to parasitoids and lacewings. I conclude that the Florida “fly free zone” protocol in its current form is not compatible with an IPM approach to commercial citrus production.