Alan A. Kirk

Variation in the Bemisia tabaci s. 1. species complex (Hemiptera: Aleyrodidae) and its natural enemies leading to successful biological control of Bemisia biotype B in the USA

Parasitoids of the Bemisia tabaci (Gennadius) species complex collected in Spain and Thailand were evaluated as biological control agents of B. tabaci biotype B in cole crops in Texas, USA. Parasitoids were identified by morphological and RAPD-PCR analyses. The most abundant parasitoid from Spain was Eretmocerus mundus Mercet with apparent field parasitism of 39-44%. In Thailand, Encarsia formosa Gahan, E. transvena Timberlake, E. adrianae Lopez-Avila, Eretmocerus sp. 1 and sp. 2 emerged, with apparent field parasitism of 1-65%. Identification and molecular classification of B. tabaci associated with parasitoid collections and in the release site in Texas were accomplished using morphological traits and nucleotide sequence comparison of the mitochondrial cytochrome oxidase I gene (COI) (700-720 bp). Collections of B. tabaci from Thailand grouped separately from B types from Arizona and Florida and the target B type from Texas, USA, a cluster from India, and other New World B. tabaci. The Spanish B. tabaci host of E. mundus which was laboratory and field-tested to achieve biological control of the B type was most closely related to non-B type B. tabaci populations from Spain and Sudan, the latter which formed a second group within the larger clade that also contained the B type cluster. Laboratory tests indicated that E. mundus from Spain parasitized more B. tabaci type B than did Eretmocerus spp. native to Texas and other exotic parasitoids evaluated. Eretmocerus mundus from Spain also successfully parasitized B. tabaci type B when field-released in a 0.94 million ha test area in Texas, and has significantly enhanced control of B. tabaci type B in California, USA. In contrast, parasitoids from Thailand failed to establish in the field in Texas, collectively suggesting a positive correlation between the centres of diversity of compatible parasitoid-host complexes.

Ovicidal and Larvicidal Activity of Conidia and Blastospores of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) Against Bemisia argentifolii (Homoptera: Aleyrodidae) with a Description of a Bioassay System Allowing Prolonged Survival of Control Insects

Fungi are the only effective entomopathogens of members of the Aleyrodidae and other homopterans because of the piercing and sucking feeding strategy of these insects. The laboratory assessment of the entomopathogenic activity of fungi often requires a prolonged period of observation. Leaf quality can be the limiting factor in bioassays of fungi against whiteflies that require longer observation periods or those that require conditions that are as close to natural ones as possible. A bioassay system is described that utilizes rooted cabbage leaves infested with the highly polyphagous whitefly, Bemisia argentifolii . Using this method, discriminating dosages of aerial conidia and blastospores of two isolates of Paecilomyces fumosoroseus (Pfr) were bioassayed against eggs and nymphs of B. argentifolii . Low, but significant, mortality (10-20%) of eggs was observed 14 days after exposure to 3.8 104 blastospores/cm2 for the Pfr 97 and European Biological Control Laboratory (EBCL) Pfr 42 isolates. Additionally...

Host range of the European, rhizome-stem feeding scale Rhizaspidiotus donacis (Hemiptera: Diaspididae), a candidate biological control agent for giant reed, Arundo donax (Poales: Poaceae) in North America

Abstract The armored scale Rhizaspidiotus donacis (Leornardi) was evaluated as a potential biological control agent of the invasive reed grass Arundo donax in North America. No-choice tests, native range field surveys and non-target host exposures were used to determine the fundamental host range of the scale collected from Caloma, Spain and Perpignan, France. Thirty-five species, including two genotypes of A. donax and seven ecotypes of Phragmites australis, along with closely related grasses, economic grasses and habitat associates were tested. In quarantine no-choice testing using releases of 200 crawlers per plant, normal development of R. donacis was observed on A. donax and A. formosana, with very limited survival to the adult stage on Spartina alterniflora and Leptochloa spp. In follow-up studies using 1000 crawlers per plant, 10 live adult females were found on Leptochloa virgata, and one adult female on Spartina alterniflora, but average adult female abundance per plant was (2580%) 26-times lower on L. virgata and over (39,090%) 100-times lower on S. alterniflora than on A. donax. Field surveys were conducted at five locations in Spain and France at which A. donax infested with R. donacis, co-occurred with two non-target species of concern and R. donacis was only found on A. donax. Six-month field host exposures in Spain using potted Leptochloa plants entwined with heavily infested A. donax confirmed that R. donacis is specific to Arundo under field conditions. Based on our results, the scale R. donacis appears to be specific to the genus Arundo and is unlikely to harm native or cultivated plants in the Americas.

SEASONAL PHENOLOGY AND NATURAL ENEMIES OF MACONELLICOCCUS HIRSUTUS (HEMIPTERA: PSEUDOCOCCIDAE) IN AUSTRALIA

Abstract Foreign exploration for natural enemies of pink hibiscus mealybug, Maconellicoccus hirsutus, was conducted in Australia from 2000 to 2002. In Queensland, the predaceous beetle Cryptolaemus montrouzieri, the predaceous drosophilid fly, Cacoxenus perspicax and the encrytid parasitoid Gyranusoidea indica were recovered. In Western Australia and the Northern Territory a predatory noctuid, Mataeomera sp., an aphelinid parasitoid Coccophagus sp., and a probable encyrtid hyperparasitoid, Coccidoctonus sp. were reared from M. hirsutus on a native Hibiscus species. A field study was conducted from February 2000 to March 2002 in Sherwood, Queensland to document the seasonal phenology of M. hirsutus in its native habitat on its preferred host, Hibiscus rosa-sinensis. Populations of the mealybug stayed at or below detectable levels for most of the study with minor population peaks in the summer months.

Evaluation of an entomopathogenic fungus, Paecilomyces fumosoroseus (Wize) Brown and Smith (Deuteromycota: Hyphomycetes) obtained from Formosan subterranean termites (Isop., Rhinotermitidae)

Abstract:  An isolate of Paecilomyces fumosoroseus was obtained from Coptotermes formosanus collected in Hong Kong, and a commercially available isolate of Metarhizium anisopliae, were both tested against C. formosanus shipped live from China. Survivorship of termites treated with a suspension of 5 × 105M. anisopliae conidia/ml and kept alone declined more rapidly than for those treated at the same concentration of P. fumosoroseus conidia. At a 5 × 106 conidia/ml concentration, no significant differences in terms of termite survivorship were observed between the two fungal species. However, among termites kept in groups of 10 after treatment, those sprayed with P. fumosoroseus conidia at either 5 × 105 or 5 × 106 conidia/ml had significantly lower survivorship than those sprayed with M. anisopliae conidia. All the cadavers of termites treated with P. fumosoroseus and kept alone sporulated and among grouped termites 29% of the cadavers sporulated. By comparison, 53% of the cadavers of termites treated with M. anisopliae and kept alone sporulated, and only 4% of the cadavers of treated termites kept in groups sporulated.

Population dynamics of Plutella xylostella (Lep., Yponomeutidae) and its parasitoids in the region of Brasilia

Abstract: The diamond back moth Plutella xylostella (L.) is the most serious pest of Brassicaceae in the world. It is resistant to many insecticides which has led to a search for alternative techniques of control, principally biocontrol‐based pest management. The impact of P. xylostella and its parasitoids was analysed in a 6‐month study of cabbage crops in the Brasilia region of Brazil, from June to November 1998. The population of the pest and its guild of parasitoids were quantified on two experimental plots at the Embrapa‐Hortaliças research station by weekly samplings. In the first cropping (June to early September), populations of P. xylostella followed a logistic growth curve leading to the destruction of the crops. In the second cropping, rains prevented the development of P. xylostella. Seven species of parasitoids were observed, Diadegma leontiniae (Brethes) and Apanteles piceotrichosus (Blanchard) being dominant. Cotesia plutellae (Kurdjumov) and Actia sp., previously more abundant, became very minor parasitoids. Significant differences were observed in specific parasitism rates between the plots. The combined parasitism rates were identical on both plots (around 23%) and were insufficient to regulate the populations of P. xylostella. Six species of hyperparasites were reared from Diadegma leontiniae and Apanteles piceotrichosus, showing a high diversity of natural enemies in this region of recent colonization by P. xylostella.

Establishment of the Armored Scale, Rhizaspidiotus donacis 1, a Biological Control Agent of Arundo donax

Author(s) :John A. Goolsby, Alan A. Kirk, Patrick J. Moran, Alex E. Racelis, John J. Adamczyk, Elena Cortes, M. Angeles Marcos Garcia, Maricela Martinez Jimenez, Kenneth R. Summy, Matthew A. Ciomperlik and Don P. A. Sands Source: Southwestern Entomologist, 36(3):373-374. 2011. Published By: Society of Southwestern Entomologists DOI: 10.3958/059.036.0314 URL: http://www.bioone.org/doi/full/10.3958/059.036.0314

Prospects for improving biological control of olive fruit fly, Bactrocera oleae (Diptera: Tephritidae), with introduced parasitoids (Hymenoptera)

Abstract Olive fruit fly is a key pest of olive and consequently a serious threat to olive fruit and oil production throughout the Mediterranean region. With the establishment of Bactrocera oleae in California a decade ago, interest was renewed in classical (introduction) biological control of the pest. Here we discuss the prospects of identifying natural enemies of B. oleae in Africa and Asia that may help reduce B. oleae populations in California and elsewhere. Based on the current understanding of Bactrocera phylogenetics, early opinions that B. oleae originated in Africa or western Asia rather than the Mediterranean region or the Near East are taxonomically and ecologically supportable. Closely related to cultivated olive, the wild olive Olea europaea cuspidata is widely distributed in southern and eastern Africa, the Arabian Peninsula, and eastwards into Asia as far as southwestern China. Little is known regarding the biology and ecology of B. oleae in Africa and eastern Asia, especially in wild olives. While the diversity of parasitoids of B. oleae in the Mediterranean region is low and unspecialized, a diverse assemblage of parasitoids is known from B. oleae in Africa. Conversely, regions in Asia have remained largely unexplored for B. oleae and its natural enemies.

Genetic differentiation among various populations of the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae)

Genetic variation among 14 populations of Plutella xylostella (Linnaeus) from USA (Geneva, New York), Brazil (Brasilia), Japan (Okayama), The Philippines (Caragan de Oyo), Uzbekistan (Tashkent), France (Montpellier), Benin (Cotonou), South Africa (Johannesburg), Réunion Island (Montvert), and five localities in Australia (Adelaide, Brisbane, Mareeba, Melbourne, Sydney) were assessed by analysis of allozyme frequencies at seven polymorphic loci. Most of the populations were not in Hardy-Weinberg equilibrium and had a deficit in heterozygotes. The global differentiation among populations was estimated by the fixation index (Fst) at 0.103 for the 14 populations and at 0.047 when populations from Australia and Japan, which differed most and had a strong genetic structure, were excluded from the analysis. By contrast, the populations from Benin (West Africa) and Brazil (South America) were very similar to each other. Genetic differentiation among the populations was not correlated with geographical distance.

Biology of Diadegma sp. (Hymenoptera: Ichneumonidae), a parasitoid of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae), from Reunion Island

The genus Diadegma have some species able to parasite Plutella xylostella (L.) (DBM). Laboratory studies were carried out on a Diadegma sp. from Reunion Island to elucidate its ability to parasite DBM larvae, and to determine the influence of the temperature on its fecundity, longevity, oviposition and the consumption of cabbage leaves by parasitized DBM larvae. Parasitism rates were close to 70% for the L2 and L3 instar, and 53% for the L4. At 15°C, there were no progeny. At 20°C and 25°C, the percentage of parasitism was near 70%. At 29°C, the percentage parasitism was similar but the number of males produced was higher. Parasitized DBM larvae consumed 35% less leaf surface than non parasitized larvae. This Diadegma sp. is a possible candidate for introduction into tropical areas, where no tropically adapted Diadegma species are known and could complement Bacillus thuringiensis treated systems.