Pathogenicity of the Entomopathogenic Fungus, <Emphasis Type="Italic">Lecanicillium muscarium</Emphasis>, against the Sweetpotato Whitefly <Emphasis Type="Italic">Bemisia tabaci</Emphasis> under Laboratory and Glasshouse Conditions

The potential for using the entomopathogenic fungus Lecanicillium muscarium to control the sweetpotato whitefly, Bemisia tabaci has been established in the laboratory by other studies. Laboratory studies however frequently overestimate the level of control achieved by biological control agents in the glasshouse. Before full-scale commercial or field development is considered, glasshouse trials are required to confirm laboratory results. Under both controlled laboratory and glasshouse conditions high mortality of second instar B. tabaci was recorded after application of L. muscarium. The potential of incorporating L. muscarium into integrated pest management strategies for the control of B. tabaci is discussed.     

Compatibility of the entomopathogenic fungus Lecanicillium muscarium and insecticides for eradication of sweetpotato whitefly, Bemisia tabaci

The compatibility of the entomopathogenic fungus Lecanicillium muscarium and chemical insecticides used to control the second instar stages of the sweetpotato whitefly, Bemisia tabaci, was investigated. The effect on spore germination of direct exposure for 24 h to the insecticides imidacloprid, buprofezin, teflubenzuron and nicotine was determined. Only exposure to buprofezin was followed by acceptable spore germination. However, all chemicals significantly reduced spore germination when compared to a water control. Infectivity of L. muscarium in the presence of dry residues of buprofezin, teflubenzuron and nicotine (imidacloprid is a systemic pesticide) on foliage were also investigated. No significant detrimental effects on the level of control of B. tabaci was recorded when compared with fungi applied to residue free foliage on either tomato or verbena plants. Fungi in combination with imidacloprid gave higher B. tabaci mortality on verbena foliage compared to either teflubenzuron or nicotine and fungi combinations. Use of these chemical insecticides with L. muscarium in integrated control programmes for B. tabaci is discussed.     

Pathogenicity of <Emphasis Type="Italic">Beauveria bassiana</Emphasis> and <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> to the tobacco spider mite <Emphasis Type="Italic">Tetranychus evansi</Emphasis>

Seventeen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and two isolates of Beauveria bassiana (Balsamo) Vuillemin were evaluated for their pathogenicity against the tobacco spider mite, Tetranychus evansi Baker & Pritchard. In the laboratory all the fungal isolates were pathogenic to the adult female mites, causing mortality between 22.1 and 82.6%. Isolates causing more than 70% mortality were subjected to dose–response mortality bioassays. The lethal concentration causing 50% mortality (LC₅₀) values ranged between 0.7×10⁷ and 2.5×10⁷ conidia ml⁻¹. The lethal time to 50% mortality (LT₅₀) values of the most active isolates of B. bassiana and M. anisopliae strains varied between 4.6 and 5.8 days. Potted tomato plants were artificially infested with T. evansi and treated with B. bassiana isolate GPK and M. anisopliae isolate ICIPE78. Both fungal isolates reduced the population density of mites as compared to untreated controls. However, conidia formulated in oil outperformed the ones formulated in water. This study demonstrates the prospects of pathogenic fungi for the management of T. evansi.     

Nematicidal activity of culture filtrate of <Emphasis Type="Italic">Beauveria bassiana</Emphasis> against <Emphasis Type="Italic">Meloidogyne hapla</Emphasis>

Culture filtrates of Beauveria bassiana at different concentrations were evaluated for nematicidal activity against the northern root knot nematode (Meloidogyne hapla); bioassays included egg hatching, mortality and infectivity on tomato plants in pots under glasshouse conditions. The percentage mortality and inhibition of hatching of root-knot nematode were directly proportional to the concentration of culture filtrates of B. bassiana. Soil drenching with culture filtrate of B. bassiana significantly reduced nematode population densities in soil and in the roots and subsequent gall formation and egg-mass production by M. hapla under glasshouse conditions.     

Phylogenetic analyses of <Emphasis Type="Italic">Uromyces viciae-fabae</Emphasis> and its varieties on <Emphasis Type="Italic">Vicia</Emphasis>, <Emphasis Type="Italic">Lathyrus</Emphasis>, and <Emphasis Type="Italic">Pisum</Emphasis> in Japan

A pea rust fungus, Uromyces viciae-fabae, has been classified into two varieties, var. viciae-fabae and var. orobi, based on differences in urediniospore wall thickness and putative host specificity in Japan. In principal component analyses, morphological features of urediniospores and teliospores of 94 rust specimens from Vicia, Lathyrus, and Pisum did not show definite host-specific morphological groups. In molecular analyses, 23 Uromyces specimens from Vicia, Lathyrus, and Pisum formed a single genetic clade based on D1/D2 and ITS regions. Four isolates of U. viciae-fabae from V. cracca and V. unijuga could infect and sporulate on P. sativum. These results suggest that U. viciae-fabae populations on different host plants are not biologically differentiated into groups that can be recognized as varieties.Contribution no. 184, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan     

Relative susceptibility of <Emphasis Type="Italic">Spodoptera litura</Emphasis> pupae to selected entomopathogenic fungi

The pupae of Spodoptera litura (Fab.), (Lepidoptera: Noctuidae), a polyphagous pest affecting common crops in Indian subcontinent, were treated with different concentrations of conidia of four isolates of entomopathogenic fungi belonging to three species, Metarhizium anisopliae var. anisopliae (Metschnikov) Sorokin (ARSEF 7487), Lecanicillium muscarium (Petch) Zare & W Gams (two isolates ARSEF 7037 and ARSEF 6118) and Cordyceps cardinalis Sung & Spatafora (ARSEF 7193) under laboratory conditions. Suspensions (10⁸/ml) of conidia harvested from Sabouraud dextrose agar yeast extract (SDAY) plates resulted in the highest mortality (85.8%) with M. anisopliae and the lowest mortality (57.3%) with C. cardinalis. The values of LC₅₀ and LC₉₀ suggested that M. anisopliae was the most virulent fungal strain followed by L. muscarium (ARSEF 7037). However, C. cardinalis was the least virulent species among the fungi used in the bioassay. In soil bioassays, drenching the soil with conidial suspensions of ARSEF 7487 and ARSEF 7037 (10⁸ conidia/g of soil) reduced the adult emergence from pupa by 81.3% and 72.5%, respectively, while premixing the sterile soil with conidia killed lesser number of pupae (62.9% by ARSEF 7487 and 54.6% by ARSEF 7037). Our findings suggest that M. anisopliae (ARSEF 7487) and L. muscarium (ARSEF 7037) are potent entomopathogens and could be developed into biocontrol agents against rice cutworm in IPM programs. Handling editor: Helen Roy     

<Emphasis Type="Italic">Beauveria bassiana</Emphasis> pathogenicity to the cherry slugworm, <Emphasis Type="Italic">Caliroa cerasi</Emphasis> (Hymenoptera: Tenthredinidae) larvae

The cherry slugworm Caliroa cerasi is a significant destructive pest of sour cherries (Prunus cerasus) in Turkey. The potential of entomopathogenic fungi for controlling C. cerasi was evaluated. The effects of exposure methods and conidial concentrations (1 × 10⁶, 1.5 × 10⁶, 1 × 10⁷ and 1.5 × 10⁷ conidia/ml) on mature larvae of C. cerasi infected by Beauveria bassiana were investigated under laboratory conditions. Larvae sprayed directly with B. bassiana conidial suspensions and larvae exposed to B. bassiana-treated leaves resulted in 100% mortality within 2.90 and 2.77 days, respectively. The median lethal time (LT₅₀) and days to mortality were highest in the 1.0 × 10⁷ concentrations of conidia for both direct spray and leaf exposure. The present study suggests that B. bassiana has good potential for control of the cherry slugworm, C. cerasi.     

<Emphasis Type="Italic">Piriformospora indica</Emphasis> and <Emphasis Type="Italic">Sebacina vermifera</Emphasis> increase growth performance at the expense of herbivore resistance in <Emphasis Type="Italic">Nicotiana attenuata</Emphasis>

A Sebacinales species was recovered from a clone library made from a pooled rhizosphere sample of Nicotiana attenuata plants from 14 native populations. Axenic cultures of the related species, Piriformospora indica and Sebacina vermifera, were used to examine their effects on plant performance. Inoculation of N. attenuata seeds with either fungus species stimulated seed germination and increased growth and stalk elongation. S. vermifera inoculated plants flowered earlier, produced more flowers and matured more seed capsules than did non-inoculated plants. Jasmonate treatment during rosette-stage growth, which slows growth and elicits herbivore resistance traits, erased differences in vegetative, but not reproductive performance resulting from S. vermifera inoculation. Total nitrogen and phosphorous contents did not differ between inoculated and control plants, suggesting that the performance benefits of fungal inoculation did not result from improvements in nutritional status. Since the expression of trypsin proteinase inhibitors (TPI), defensive proteins which confer resistance to attack from Manduca sexta larvae, incur significant growth and fitness costs for the plant, we examined the effect of S. vermifera inoculation on herbivore resistance and TPI activity. After 10 days of feeding on S. vermifera-inoculated plants, larval mass was 46% higher and TPI activity was 48% lower than that on non-inoculated plants. These results suggest that Sebacina spp. may interfere with defense signaling and allow plants to increase growth rates at the expense of herbivore resistance mediated by TPIs.     

Pleiotropic effect of the insertion of the <Emphasis Type="Italic">Agrobacterium rhizogenes rolD</Emphasis> gene in tomato (<Emphasis Type="Italic">Lycopersicon esculentum</Emphasis> Mill.)

The Agrobacterium rhizogenes rolD gene, coding for an ornithine cyclodeaminase involved in the biosynthesis of proline from ornithine, has been inserted in Lycopersicon esculentum cv Tondino with the aim of studying its effects on plant morphological characters including pathogen defense response. The analysis of plants transgenic for rolD did not show major morphological modifications. First generation transgenic plants however were found to flower earlier, and showed an increased number of inflorescences and higher fruit yield. Transformed plants were also analysed for parameters linked to pathogen defense response, i.e. ion leakage in the presence of the toxin produced by the fungus Fusarium oxysporum f. sp. lycopersici, and expression of the pathogenesis-related PR-1 gene. All the plants harbouring the rolD gene were shown to be more tolerant to the toxin in ion leakage experiments, with respect to the untransformed regenerated controls and the cv Tondino. PR-1 gene expression was quantitated by means of real-time PCR both at the basal level and after treatment with salicylic acid, an inducer of Systemic Acquired Resistance. In both cases the amount of PR-1 mRNA was higher in the transgenic plants. It seems therefore that the transformation of tomato plants with rolD could lead to an increased competence for defense response, as shown by toxin tolerance and increased expression of the Systemic Acquired Resistance marker gene PR-1. The results are finally discussed in view of their possible economic relevance.Communicated by G. Wenzel     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-<Emphasis Type="Italic">tumefaciens</Emphasis>-mediated transformation of<Emphasis Type="Italic"> Helminthosporium turcicum</Emphasis>, the maize leaf-blight fungus

Agrobacterium tumefaciens has the ability to transfer its T-DNA to plants, yeast, filamentous fungi, and human cells and integrate it into their genome. Conidia of the maize pathogen Helminthosporium turcicum were transformed to hygromycin B resistance by a Agrobacterium-tumefaciens-mediated transformation system using a binary plasmid vector containing the hygromycin B phosphotransferase (hph) and the enhanced green fluorescent protein (EGFP) genes controlled by the gpd promoter from Agaricus bisporus and the CaMV 35S terminator. Agrobacterium-tumefaciens-mediated transformation yielded stable transformants capable of growing on increased concentrations of hygromycin B. The presence of hph in the transformants was confirmed by PCR, and integration of the T-DNA at random sites in the genome was demonstrated by Southern blot analysis. Agrobacterium-tumefaciens-mediated transformation of Helminthosporium turcicum provides an opportunity for advancing studies of the molecular genetics of the fungus and of the molecular basis of its pathogenicity on maize.     

Natural Infections Caused by the Fungus <Emphasis Type="Italic">Beauveria bassiana</Emphasis> as a Pathogen of <Emphasis Type="Italic">Musca domestica</Emphasis>in the Neotropic

A survey for entomopathogenic fungi of Musca domestica adults was conducted in poultry houses in La Plata, Buenos Aires province, Argentina, during the years 2002 and 2003. Adult house flies were found infected with the fungus Beauveria bassiana (Bals.) Vuill. (Deuteromycotina: Hyphomycetes) from field collections, with a natural infected prevalence between 0.4–1.45%. This is the first record of natural infections of house flies caused by B. bassiana for the neotropics. Pathogenicity assays under laboratory conditions showed 94% adult mortality at 14 days post challenge. CIC fellow     

Close-Range Host Searching Behavior of the Stemborer Parasitoids <Emphasis Type="Italic">Cotesia sesamiae</Emphasis> and <Emphasis Type="Italic">Dentichasmias busseolae</Emphasis>: Influence of a Non-Host Plant <Emphasis Type="Italic">Melinis minutiflora</Emphasis>

Studies were conducted on the host searching behavior of the larval parasitoid Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) and the pupal parasitoid Dentichasmias busseolae Heinrich (Hymenoptera: Ichneumonidae), both of which attack lepidopteran (Crambidae, Noctuidae) cereal stemborers. The behavior of D. busseolae was observed in a diversified habitat that consisted of stemborer host plants (maize, Zea mays L. and sorghum, Sorghum bicolor (L). Moench (Poaceae)) and a non-host plant (molasses grass, Melinis minutiflora Beauv. (Poaceae)), while C. sesamiae was observed separately on host plants and molasses grass. In previous olfactometer studies, C. sesamiae was attracted to molasses grass volatiles while hboxD. busseolae was repelled. The aim of the present study was to investigate the influence of molasses grass on close-range foraging behavior of the parasitoids in an arena that included infested and uninfested host plants. Dentichasmias busseolae strongly discriminated between host and non-host plants, with female wasps spending most of the time on infested host plants and least time on molasses grass. Likewise, C. sesamiae spent more time on uninfested and infested host plants than it did on molasses grass in single choice bioassays. While on infested plants, the wasps spent more time foraging on the stem, the site of damage, than on other areas of the plant. Overall, the results indicate that presence of the non-host plant does not hinder close range foraging activities of either parasitoid.     

A single-base deletion mutation in <Emphasis Type="Italic">SlIAA9</Emphasis> gene causes tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis>) <Emphasis Type="Italic">entire</Emphasis> mutant

The entire (e) locus of tomato (Solanum lycopersicum L.) controls leaf morphology. Dominant E and recessive e allele of the locus produce pinnate compound and complex reduced leaves. Previous research had indicated that SlIAA9, an Aux/IAA gene, was involved in tomato leaf morphology. Down-regulation of SlIAA9 gene by antisense transgenic method decreased the leaf complex of tomato and converted tomato compound leaves to simple leaves. The leaf morphology of these transgenic lines was similar with leaf morphology of tomato entire mutant. In this paper, we report that a single-base deletion mutation in the coding region of SlIAA9 gene results in tomato entire mutant phenotypes.     

Influence of <Emphasis Type="Italic">Lecanicillium attenuatum</Emphasis> on the development and reproduction of the cotton aphid, <Emphasis Type="Italic">Aphis gossypii</Emphasis>

The activity of entomopathogens on insect pests has been investigated for many species but the influence of entomopathogenic fungi on factors other than mortality relating to population increase has not been frequently studied. The influence of Lecanicillium attenuatum CS625 (=Verticillium lecanii CS625) on development and reproduction of cotton aphid (Aphis gossypii) was investigated. A conidia suspension of the isolate was applied onto first instar nymphs. Increased spore concentration did not significantly affect each nymphal stage, total nymphal period, pre-reproductive period and the age of first larviposition. A significant dose effect on reduction of life span, reproductive period and fecundity was observed in 1st and 3rd instars after spore application. When conidia were applied to 1st instars, life span was significantly reduced to 10.8 and 8.4 days at 1 × 10⁴ and 1 × 10⁸ conidia/ml, respectively from 12.2 days in the control. During the life span, total fecundity was 41 ± 7.3, 26 ± 0.8 and 22 ± 5.7 nymphs per female at 1 × 10⁴, 1 × 10⁶ and 1 × 10⁸ conidia/ml, respectively compared with 51 ± 2.0 nymphs per untreated female. Reproduction period was also significantly shortened with increasing spore concentration. Application of spores to 3rd instars showed a similar trend. However, daily fecundity of individual aphids was not affected by spore dose. It was concluded that the isolate of L. attenuatum is able to affect populations of cotton aphid by reducing life span and total fecundity as well as by killing the aphids directly.     

Effect of a turnip rape <Emphasis Type="Italic">(Brassica rapa)</Emphasis> trap crop on stem-mining pests and their parasitoids in winter oilseed rape <Emphasis Type="Italic">(Brassica napus)</Emphasis>

Concerns about the negative effects of chemical control of oilseed rape (Brassica napus L.) pests on non-target species, human safety, and development of insecticide resistance, require alternative control strategies such as the use of trap crops and biocontrol to be developed. Psylliodes chrysocephala(L.) (Coleoptera: Chrysomelidae) (cabbage stem flea beetle) and Ceutorhynchus pallidactylus (Marsh.) (Coleoptera: Curculionidae) (cabbage stem weevil) are two major stem-mining pests of oilseed rape. This study investigated the phenology of these pests and their main parasitoids in the UK, the potential use of turnip rape (Brassica rapa L.) as a trap crop to reduce oilseed rape infestation, and the effects of insecticide treatment on pest incidence and larval parasitism. Water trap samples, plant dissections and pest larval dissections were done to determine: the incidence of adult pests and their parasitoids, the level of plant infestation by the pests and percentage larval parasitism, respectively. The turnip rape trap crop borders reduced P. chrysocephalabut not C. pallidactylus infestation of oilseed rape plots. Treatment of the trap crop with insecticide had little effect on either pest or parasitoid incidence in the oilseed rape. TersilochusmicrogasterSzép. andT. obscurator Aub. (Hymenoptera: Ichneumonidae) were the main larval parasitoids of P. chrysocephalaand C. pallidactylus, respectively. Tersilochus microgasteris reported for the first time in the UK. The implications for integrated pest management are discussed.     

Effects of <Emphasis Type="Italic">Paecilomyces fumosoroseus</Emphasis> and <Emphasis Type="Italic">Encarsia formosa</Emphasis> on the control of the greenhouse whitefly: preliminary assessment of a compatability study

The effect of separate and combined activity of Paecilomyces fumosoroseus Wize (Brown and Smith) Trinidadian strain T11 and the parasitoid, Encarsia formosa Gahan, was assessed on populations of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood), infesting Phaseolus vulgaris L. (French bean) and Pelargonium x domesticum (regal geranium) plants in replicate experiments. When infested bean and geranium plants were exposed to E. formosa for 2 days, and 4 days later sprayed with P. fumosoroseus blastospores, whitefly percent mortality was 99.5% and 75.5%, 94.6% and 59.4% for experiments 1 and 2, respectively. Treatment of infested bean plants with either E. formosa or P. fumosoroseus resulted in 87.8% and 78.7%, 73.1% and 97.0% whitefly mortality for experiments 1 and 2, respectively, while similar treatment of infested geranium plants resulted in 9.2% and 52.8%, 34.3% and 64.5% whitefly mortality for experiments 1 and 2, respectively. Our results support the use of E. formosa and P. fumosoroseus in combination in Experiment 1 for the treatment of whitefly infested P. vulgaris plants since a significant difference in mortality is observed than when either E. formosa or P. fumosoroseus is applied alone. However, in experiment 2, the combination treatment on P. vulgaris was no more effective than spraying P. fumosoroseus alone. On P. x domesticum plants, only P. fumosoroseus alone is needed for efficient control of the whitefly compared to the combination treatment. The relative timing of parasitoid oviposition and fungal infection are critical in determining the outcome of the interaction and are plant host dependent.     

The expression of analgesic-antitumor peptide (<Emphasis Type="Italic">AGAP</Emphasis>) from Chinese <Emphasis Type="Italic">Buthus</Emphasis><Emphasis Type="Italic">martensii</Emphasis> Karsch in transgenic tobacco and tomato

The present study aimed to obtain analgesic-antitumor peptide (AGAP) gene expression in plants. The analgesic-antitumor peptide (AGAP) gene was from the venom of Buthus martensii Karsch. Previous studies showed that AGAP has both analgesic and antitumor activities, suggesting that AGAP would be useful in clinical situations as an antitumor drug. Given that using a plant as an expression vector has more advantages than prokaryotic expression, we tried to obtain transgenic plants containing AGAP. In the present study, the AGAP gene was cloned into the plasmid pBI121 to obtain the plant expression vector pBI-AGAP. By tri-parental mating and freeze–thaw transformation, pBI-AGAP was transformed into Agrobacterium tumefaciens LBA4404. Tobacco (Nicotiana tabacum) and tomato (Lycopersicom esculentum) were transformed by the method of Agrobacterium-mediated leaf disc transformation. The transformants were then screened to grow and root on media containing kanamycin. Finally, transformations were confirmed by analysis of PCR, RT-PCR and western blotting. The results showed that the AGAP gene was integrated into the genomic DNA of tobacco and tomato and was successfully expressed. Therefore, the present study suggests a potential industrial application of AGAP expressed in plants.     

A new species of <Emphasis Type="Italic">Discostroma</Emphasis> and its anamorph <Emphasis Type="Italic">Seimatosporium</Emphasis> with two morphological types of conidia,isolated from the stems of <Emphasis Type="Italic">Paeonia suffruticosa</Emphasis>

Conidia of two morphologically different types, one with a basal appendage only and the other with appendage at both ends, were isolated from the stems of Paeonia suffruticosa. Single conidial isolates of both types of conidia yield identical colonies, which then produced both types of conidia on agar media depending on temperature, thus showing that both types of conidia belong to the same fungus. Seimatosporium botan is described based on its morphological characteristics. The teleomorph of the fungus was first found on sterilized P. suffruticosa stems placed on water agar, when grown at 5°C for 2 months in 12-h photoperiod. Discostroma botan is described for this fungus. The teleomorph is also found on the same host in the field.     

Host preferences and biotic potential of <Emphasis Type="Italic">Trialeurodes vaporariorum</Emphasis> and <Emphasis Type="Italic">Bemisia tabaci</Emphasis> (Hemiptera: Aleyrodidae) in tomato and pepper

Whiteflies Bemisia tabaci (Gennadius) and Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) are important pests in pepper (Capsicum annuum L.) and tomato (Solanum lycopersicum L.) crops in many countries. Contrary to what is observed for all other countries, in Uruguay, B. tabaci is mainly found on pepper and rarely on tomato, while T. vaporariorum is exclusively found on tomato. This study tested the oviposition preferences and biotic potential of these two whiteflies reared on both host plants. The developmental time, survival rates, longevity, fecundity and main population parameters were characterized. Both whitefly species showed different preference patterns regarding their host plants. T. vaporariorum preferred tomato instead of pepper to oviposit. Their developmental time is longer on pepper. B. tabaci preferred pepper, but the difference from tomato was not very strong. Pepper affects the biotic expression of T. vaporariorum negatively, while B. tabaci is able to develop equally on both host plants. These results show that the distribution differences of both whiteflies observed on both host plants could have a biological basis.