First Record of Teratopactus nodicollis (Coleoptera: Curculionidae) in Dry Bean (Phaseolus vulgaris)

Observations on the bioecology and damage of Teratopactus nodicollis Boheman on Phaseolus vulgaris were carried out on field samples by assessing the number of larvae and root damage in 40?ha of a dry bean field from the Federal District, Brazil (16°4??28.41???W; 47°30??21.13???S). Larvae caused the greatest damage at the stage of germination, emergence, and primary leaves, producing 50?% stand reduction. Most larvae pupated in August and September, and adult emergence occurred in middle October. Some larvae were infected with the fungus Metarhizium spp., a biological agent that would be naturally controlling this insect.     

Epizootics and behavioral alteration in the arctiid caterpillar Chionarctia nivea (Lepidoptera: Arctiidae) caused by an entomopathogenic fungus, Entomophaga aulicae (Zygomycetes: Entomophthorales)

We observed epizootics and behavioral alteration in the arctiid caterpillar Chionarctia nivea after infection by an entomopathogenic fungus, Entomophaga aulicae, in April at a riverbank in Kyoto Prefecture, central Japan. The density of arctiid cadavers infected with E. aulicae was 1.31 individuals/m². The critically ill caterpillars crawled up the dead stems of grasses and herbs such as the common reed Phragmites communis and the Japanese mugwort Artemisia indica var. maximowiczii to die at and near the highest parts of the stems, while the healthy larvae usually wandered on the ground and fed on the leaves of small herbs. This behavioral difference could be caused by infection with E. aulicae to enhance dispersal of conidia by active discharge in Entomophthorales with the aid of wind and rainfall.     

Haliphthoros milfordensis isolated from black tiger prawn larvae (Penaeus monodon) in Vietnam

A marine fungus was isolated from the black tiger prawn Penaeus monodon at Nha Trang, Vietnam, on March 20, 2001 and named isolate NJM 0131. The fungus was identified as Haliphthoros milfordensis from the characteristics of asexual reproduction, and its physiological characteristics were investigated. Although the optimum temperature for growth of the isolate was 25°–30°C, the fungus grew at a wide range of temperatures (15°–40°C). H. milfordensis grew well in 50%–100% seawater, but poorly in PYG agar containing 1.0%–5.0% NaCl and KCl. The fungus grew at a wide range of pH (4.0–11.0) with the optimum pH value of 7.0–9.0. The isolate also showed pathogenicity to swimming crab larvae (Portunus trituberculatus) by artificial infection, but mortality was not high. This is the first report of disease in the black tiger prawn P. monodon in Vietnam caused by H. milfordensis.     

Incidence of Entomophthora sp. and other natural control agents in populations of Pseudoplusia includens and Trichoplusia ni

A species of Entomophthora was observed as a mortality factor in populations of Pseudoplusia includens and Trichoplusia ni in cotton and soybean fields throughout Alabama. Resting spores appear identical to those of Tarichium gammae. The incidence of this fungus in host populations, as well as other disease agents and parasites, was determined from larval samples collected throughout the State. Entomophthora infected 8% of all loopers collected on cotton as compared to 35% on soybeans. T. ni nuclear polyhedrosis virus infected 41% of all loopers collected from cotton but no mortality attributable to virus was found in loopers collected on soybeans, which were predominantly P. includens.Studies in 1969 and 1970 on the incidence of Entomophthora sp. in a population of P. includens infesting soybeans in central Alabama have shown it to infect between 50 and 95% of all individuals present from early August through mid-September, the period of densest abundance of the caterpillars. Spicaria sp. was also present during August and September but did not contribute significantly to reduction in population levels until late in the season. Parasites accounted for less than 1% of all mortality in each year and predator populations were very small during the periods of observation.     

A mycosis caused by Lagenidium sp. in laboratory-reared larvae of the Dungeness crab,Cancer magister,and possible chemical treatments

A mycosis in larvae of the Dungeness crab, Cancer magister, was observed about 48 hr after they had molted to second-stage zoeae in the laboratory during a chronic bioassay. The fungus was of the genus Lagenidium and caused about 40% mortality of larvae before the test was terminated. Hyphal development and subsequent sporulation of the fungus was observed over a range of 0–32‰ salinity, with an optimum around 16‰. Bioassays of eight fungicides and the herbicide trifluralin, using the larvae and fungus in separate tests, were performed to explore means of chemical treatment. Trifluralin was the most satisfactory of the chemicals screened, with captan, Cu²⁺, and benomyl also giving good results for certain treatment intervals of up to 96 hr. Malachite green was toxic to larvae at concentrations inhibiting the fungus.     

Mass production,infectivity, and field application studies with the entomogenous fungus Paecilomyces farinosus

Hyphal bodies (HB) of the entomogenous fungus Paecilomyces farinosus mass produced in shaken liquid cultures are infective per os and topically to Spodoptera exigua larvae. Pathogenicity of HB was greatest at pH 5.5. It was reduced by exposure for more than one-half hour to temperatures above 30°C. P. farinosus infected, killed, and produced mycelia on the surface of first-instar S. exigua larvae at a temperature—relative humidity combination as low at 15°C and 70% RH. Using two types of microdroplet applicators (droplet in the size range 1–30 and 30–90 μm, respectively) under field conditions, HB were delivered to distances of 76 m from the site of spraying. The number of HB deposited on the leaf surfaces of treated crops caused mortality of 70 to 90% in bioassayed larvae.     

Larval Mortality Factors of <Emphasis Type="Italic">Spodoptera Littoralis</Emphasis> in the Azores

Mortality among larval developmental stages of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), was determined by weekly sampling on weeds in a pasture on São Miguel Island (Azores, Portugal), from August to December, over a 3-year period (1999–2001). In all the years surveyed, larvae of S. littoralis usually appeared in pastures after the third week of August, with higher abundances in September and the beginning of October. Three different factors causing larval mortality were identified: one fungal pathogen, Furia virescens (Thaxter) Humber (Zygomycetes: Entomophthoraceae), two nucleopolyhedroviruses and one larval parasitoid, Meteorus communis (Cresson) (Hymenoptera: Braconidae). The percentages of dead larvae infected by virus or fungus were significantly higher than the other causes of mortality, regardless of the year. Furthermore, the percentage of larvae that died due to virus contamination was generally higher than the percentage of larvae infected by fungus. Significant correlations between the environmental factors and the percentage of larvae infected by virus or by fungus, were only observed during 2001. In 2001, the prevalence of fungal infection was negatively correlated with that of viral infection although prevalences of these two agents were positively correlated in both 1999 and 2000. These results show that virus and fungus are potential biological control agents for S. littoralis in Azores.     

Mutualism between a phytopathogenic fungus (Botrytis cinerea) and a vineyard pest (Lobesia botrana). Positive effects on insect development and oviposition behaviour

In vineyards, larvae of the grape berry moth (Lobesia botrana) favour the development of the grey mould fungus Botrytis cinerea. To study the possibility of a mutualistic relationship between these organisms, we investigated the effects of the fungus on the development and oviposition behaviour of the insect. Larvae were reared on whole plants infected or uninfected with the fungus, or on an artificial diet containing either infected grape berries or the mycelium. The presence of the fungus consistently led to a reduction in the duration of insect development (4–6 d) and mortality (20–67 %). The fecundity increased from 12 to 76 %. Moreover, the fact that the females laid eggs preferentially on fungus-infected grape berries confirms the mutualistic association between these organisms. The fungus alone contributed to the positive effects. We showed the existence of a mutualistic relationship between the two organisms which are both damaging to vineyards.     

Life history ofSmicronyx guineanus andSm. Umbrinus (Col.: Curculionidae) onStriga hermonthica (Scrophulariaceae)

The life history ofSmicronyx guineanus andSm. umbrinus, weevils attackingStriga hermonthica, was studied in Burkina Faso, West Africa. Field experiments were conducted in 1992 and 1993 at Kaya, in fields of sorghum (Sorghum bicolor (L.) Moench and pearl millet (Pennisetum americanum (L.) K. Schum. (syn.P. typhoides (Burm.) Stapf &; Hubb). The weevils are univoltine; the adults emerge in late August, mate and eggs are laid in the ovary ofStriga inflorescence. Larval feeding in the ovary causes galling and prevents seed production. The main damage toStriga seed capsule is caused by the larvae of at least twoSmicronyx species. Last-instar larvae drop to the soil and bury themselves to a depth of 1–15 cm, pupate and enter into dormancy. Most pupae are found in the upper 5–10 cm of the soil. The pupal period lasts from late October to late July. In May, we found 75.6% of pupae against 24.4% of adults in dormancy.     

A mosquito parasite from a mosquito predator

The fungus Coelomomyces macleayae has been reported from treehole mosquito larvae of three Aedes subgenera in Australia, Fiji, and the United States. This fungus is now recorded for the first time from a mosquito of the genus Toxorhynchites, the large predatory larvae of which are of some importance in the naturalistic control of associated mosquito pests and vectors. A single parasitized larva of T. rutilus septentrionalis was collected from a magnolia treehole (previously used for A. triseriatus infection experiments) near West Lake, Louisiana, in September, 1971. Larval A. triseriatus and Orthopodomyia signifera were also present but were uninfected.     

Susceptibility of the Colorado Potato Beetle and the Sugarbeet Wireworm to Steinernema feltiae and S. glaseri

In laboratory tests, larvae of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), and the sugarbeet wireworm (SBW), Limonius californicus (Mannerheim), were exposed to the nematodes Steinernema feltiae Filipjev (Mexican strain) (= Neoaplectana carpocapsae) and S. glaseri Steiner in soil. S. feltiae caused significantly higher mortality in SBW larvae than did S. glaseri, but both nematode species were equally effective against CPB larvae. The minimum concentration of S. feltiae for 100% mortality of CPB larvae after 13 days was 157 nematodes/cm² of soil, and the LC₅₀ based on 6-day mortality was 47.5 nematodes/cm²; in contrast, 100% mortality of SBW larvae was not achieved with even the highest concentration tested, 393 nematodes/cm². CPB adults emerging from nematode-contaminated soil were not infected. In field cage tests, S. feltiae applied to the soil surface at the rates of 155 and 310 nematodes/cm² soil caused 59% and 71% mortality, respectively, of late-fourth-instar spring-generation CPB, and 28% and 29% mortality, respectively, of SBW. No infection was obtained when larvae of summer generation CPB and SBW were placed in the same cages approximately 6 weeks after nematodes were applied to the soil. Inundative soil applications of S. feltiae, though cost prohibitive at present, were effective in reducing caged CPB and SBW field populations.     

Susceptibility of Heliothis zea larvae to Nomuraea rileyi at various temperatures

Laboratory studies were conducted to determine the susceptibility of various larval instars of Heliothis zea to different spore doses of Nomuraea rileyi at constant and variable temperatures. The fungus was most effective at 20° and 25°C, with a mortality of 80% and 71%, respectively. At 15°C the disease progressed very slowly with larval mortality occurring in 12–28 days post-treatment. Conversely, at temperature ranges above 15°C, the mortality of the larvae occurred in 6–12 days. Three different combinations of variable temperatures included 20–30°, 25–30°, and 20–35°C, but mortality did not exceed 46%. Larvae in the third to fifth instars were more susceptible to infection than were those in the first and second instars.     

Egg parasitism of the yellow rice borer,Scirpophaga incertulas [Lep.: Pyralidae] in Bangladesh deepwater rice

Studies on deepwater rice in Bangladesh from 1977 to 1980 showed that 61–89% of the egg masses of the yellow rice borer,Scirpophaga incertulas (Walker), were attacked by hymenopterous parasites. Egg parasitism increased from 43–48% in broods 2–4 (May–August) to 64–88% in broods 5–6 (September–November). Parasitism was reduced in broods 4 and 5 in 1979 (because of lower host densities) and in 1980 (possibly due to extreme late flooding). Telenomus rowani (Gahan), active throughout the year, parasitized 64% of the eggs in the masses it attacked, 32 larvae/mass surviving.Tetrastichus schoenobii Ferrière first appearing at medium host densities, increased rapidly to attack half of the brood 5 and 6 masses. More than 98% of the eggs in the attacked masses were parasitized, leaving only 1.6 surviving larvae/mass. In 1979 its appearance was delayed by 10 weeks and fewer masses were parasitized due to lower host densities.Trichogramma japonicum Ashmead andTelenomus sp. (a new record) were less important. Multiple parasitism of masses rose from 7% in brood 2 to 28% in brood 5. Egg parasites clearly reduce the numbers ofS. incertulas, a major pest, and thus probably improve the yields of deepwater rice.     

Susceptibility of different life stages of the European cherry fruit fly,Rhagoletis cerasi,to entomopathogenic fungi

The effects of six fungus isolates on the mortality of different life stages of the European cherry fruit fly, Rhagoletis cerasi (Diptera: Tephritidae), were assessed in a series of laboratory experiments to find an isolate suitable for biological control. In a first step, the effects of fungus treatments on mortality, mycosis and fecundity of adult flies at a concentration of 10⁷ conidia/ml were evaluated. All fungus isolates caused mycosis but virulence varied considerably among the isolates. Beauveria bassiana and Isaria fumosorosea caused 90–100% mortality and had the strongest influence on fecundity. Metarhizium anisopliae also induced high rates of mortality, while the pathogenicity of Isaria farinosa was low. The effects of lower conidia concentrations and the influence of the age of flies were assessed in a second step. Higher conidia concentrations generally resulted in a higher mortality. B. bassiana was most efficient at low concentrations. Young flies showed lower mortality rates than older flies but, sub‐lethal effects on eclosion rate of eggs were greater in younger flies. Finally, the effects on L₃ larvae were tested: none of the fungus isolates induced mortality in more than 25% of larvae. As L₃ larvae and pupae are not susceptible to fungus infection, field control of R. cerasi should be focused on adult flies.     

金龟子绿僵菌在森林土壤中的分布及对松墨天牛致病性测定

松墨天牛是重大森林植物检疫性病害——松材线虫病的主要媒介昆虫。本研究于2005年8月～2006年8月从福建、江西两省共110个林分样区（其中松林88个样区）采集土壤样品330份,采用选择性培养基分离土壤中的金龟子绿僵菌。从21个样区的26份土样中分离出的金龟子绿僵菌占采集样区的19.1%和样品的7.9%,成菌落数（CFU）500～72500CFU/g,表明金龟子绿僵菌在森林土壤中有较为广泛的分布。对分离到的9个产孢量高的菌株,采用浸渍法（1×10⁷孢子/mL）接种3～4龄健康松墨天牛幼虫,采用跗节接种法接种2～15日龄健康成虫,测定其致病力。结果表明,MaYTTR-03、MaYTTR-04菌株对松墨天牛幼虫和成虫均有较高致病力,表现出良好的生防潜力。     

金龟子绿僵菌在森林土壤中的分布及对松墨天牛致病性测定

松墨天牛是重大森林植物检疫性病害——松材线虫病的主要媒介昆虫。本研究于2005年8月～2006年8月从福建、江西两省共110个林分样区(其中松林88个样区)采集土壤样品330份,采用选择性培养基分离土壤中的金龟子绿僵菌。从21个样区的26份土样中分离出的金龟子绿僵菌占采集样区的19．1％和样品的7．9％,成菌落数(CFU)500～72500CFU/g,表明金龟子绿僵菌在森林土壤中有较为广泛的分布。对分离到的9个产孢量高的菌株,采用浸渍法(1×10~7孢子/mL)接种3～4龄健康松墨天牛幼虫,采用跗节接种法接种2～15日龄健康成虫,测定其致病力。结果表明,MaYTTR-03、MaYTTR-04菌株对松墨天牛幼虫和成虫均有较高致病力,表现出良好的生防潜力。     

Effectiveness of the white halo fungus, Cephalosporium lecanii, against field populations of coffee green bug, Coccus viridis

The white halo fungus, Cephalosporium lecanii, was highly effective in the control of the coffee green bug, Coccus viridis, under field conditions. With two fortnightly applications of 16 × 10⁶ spores/ml, it caused the maximum mortality (73.1%) of the bugs 2 weeks after second application. The mortality rate was increased in the same count to 97.6% when Tween 20 (0.05%) was added to the spore suspension. Addition of starch, Lerolat N 100, Erkentrol, and Wannin to the spore suspension also increased the pathogenicity of the fungus. Among the three insecticides tested along with the fungus, 0.225% Orthene and 0.1% DDT failed to increase the mortality rate of the green bugs while 0.1% BHC hampered the effectiveness of the fungus greatly. In another trial, the fungus was applied at five different dosages and 16 × 10⁶ spores/ml was found adequate to cause a 77.9% mean mortality. The fungus was more effective as high-volume spray than as a low-volume spray. The pathogen, when tested in a drought period, was comparatively less effective, and addition of the humectant glycerol increased the mortality of the bugs due to fungus infection.     

Response of Galleria mellonella (Lepidoptera: Pyralidae) and Tenebrio molitor (Coleoptera: Tenebrionidae) to Spiroplasma citri inoculation

Injections into 4th instar larvae of Galleria mellonella using either in vitro or in vivo inoculum of the BR-6 isolate of Spiroplasma citri, propagated for one to nine passages, caused 5.7 to 24.7% mortality. Weight gain of the larvae injected at their 4th, 5th, and 6th instar was reduced in the first 4 days after inoculation but final pupal weight of the survivors was not significantly affected. Fourth instar larvae pupated within 10 days after the injection, but more larvae (6–13%) injected with 5th- to 9th-passage cultures pupated 5 or more days later than did larvae injected with 1st to 4th-passage cultures (0–3%). As many as one-third of the injected larvae developed into deformed pupae, with some external appendages missing or with a reduced and distorted thorax or abdomen with uneven tanning of the integument. Spiroplasma multiplied to dense concentrations (10⁸ to 10⁹/ml) in hemolymph smears from injected larvae incubated under oil. Larvae of Tenebrio molitor were not susceptible to S. citri by injection or feeding and G. mellonella were not susceptible by feeding. Transmissibility of S. citri by leafhopper vector to celery and periwinkle plants was retained after propagation for nine successive passages during 7 months in a nonhost insect such as Galleria.     

Pathogenesis of infection by the hyphomycetous fungus,Tolypocladium cylindrosporum inAedes sierrensis andCulex tarsalis [Dip.: Culicidae]

The mode of infection and cycle of development ofTolypocladium cylindrosporum Gams was examined inAedes sierrensis andCulex tarsalis. Larvae were found to be infected through the external cuticle, the pharynx and the midgut. Blastospores and conidia were both infective although for equal numerical concentrations blastospores proved more virulent causing high mortality within the first 48 h after inoculation (80 % for L2 larvae exposed to 5×10⁵ spores/ml), while conidia generally took 7–10 days to produce the same results. Sporulation did not occur on submerged cadavers. Conidia were produced only on floating cadavers in contact with air. Conidial production on floating 4th instar larvae was found to average 1.8×10⁷ conidia/larva. Invasion of the haemocoele and fairly extensive growth of the fungus almost invariably occurred before larvae were killed. This was particularly true forAedes sierrensis larvae. Details are presented of growth within the host and post-mortem penetration of the fungus out of the cadaver. AdultA. sierrensis sprayed with a conidial suspension proved susceptible to infection with 100 % mortality being recorded at 10 days. Infections originated in the thorax, suggesting, the integument or possibly the thoracic spiracles to be the most probable site of infection.     

Effectiveness of Steinernema spp. and Heterorhabditis bacteriophora against Popillia japonica in the Azores

Steinernema carpocapsae (Breton strain), S. glaseri, and Heterorhabditis bacteriophora were evaluated for their potential to control immature stages of the Japanese beetle, Popillia japonica, on Terceira Island (the Azores). In bioassays carried out at temperatures higher than 15 C, S. glaseri and H. bacteriophora caused 100% mortality of larvae, whereas S. carpocapsae caused 56% larval mortality. At temperatures slightly below 15 C, only S. glaseri remained effective. In field plots, in September, S. glaseri and S. carpocapsae reduced larval populations by 91% and 44%, respectively, when applied at the rate of 10⁶ nematodes/m². In April, S. glaseri caused 31% reduction in numbers of larvae, but S. carpocapsae was ineffective. In colder months (November-February) neither steinernematids nor H. bacteriophora reduced larval populations. Increasing the application rate from 10⁶ to 5 x 10⁶ infective stage S. glaseri per m² increased efficacy from 63% to 79% mortality.