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At least 649 records · Page 36Linked to original sources
PubMed1996

The biology and predatory potential of notonectid bug, Enithares indica (Fabr) against mosquito larvae.

The biology of a notonectid bug Enithares indica against immatures of Anopheline, Culicine and Aedine mosquitos was studied in the laboratory. The life cycle of the bug consists of the egg and five nymphal stages and takes about 64 +/- 1.54 days for completion. All stages of E. indica have good predatory potential. It can be used as a biological control agent in an integrated disease vector control program.

Aedes↗
PubMed2005

The predatory capability of Arthrobotrys cladodes var. macroides in the control of Haemonchus contortus infective larvae.

One hundred compost samples were examined for the presence of nematophagous fungi on the sheep farms of Mazanderan, province, Iran. Arthrobotrys cladodes var. macroides (IRAN 677C=CBS 143565) was isolated from 3% of the samples examined. Nematophagous activity of this fungus which was shown for the first time in this study, revealed the addition of 1000, 8000, 20000 and 100000 conidia per gram of feces of sheep reduced significantly (P<0.001) the number of Haemonchus contortus infective larvae in the feces by 41.71%, 63, 27%, 73.49% and 94.96%, respectively. These results show that A. cladodes var. macroides is a promising candidate for biological control of H. contortus.

Animals↗
PubMed2002

Post-harvest biological control by Pantoea agglomerans (CPA-2) on Golden Delicious apples.

AIMS: To investigate the potential of Pantoea agglomerans to control the major post-harvest diseases on Golden Delicious apples. METHODS AND RESULTS: In laboratory trials, a high level of control of Penicillium expansum, Botrytis cinerea and Rhizopus stolonifer was obtained with P. agglomerans. In semi-commercial trials at 1degrees C in air and a low oxygen atmosphere, the reduction of blue mould was 81% and 100%, respectively, and control of grey mould was achieved equally with P. agglomerans and imazalil. In trials at 1degrees C and seven atmosphere conditions, maximum reduction in decay was 80% obtained at 3% O2-6% CO2. The population of P. agglomerans on apples followed the same pattern under all three atmosphere conditions studied. CONCLUSIONS: Pantoea agglomerans could be used effectively on apples under a wide range of temperature and atmosphere conditions. SIGNIFICANCE AND IMAPCT OF THE STUDY Pantoea agglomerans can be used as a biocontrol agent on apples at 8 x 10(7) cfu ml-1, the same concentration as in pears. This will facilitate the application of this biological control agent by the growers in packing houses.

Food Preservation↗
PubMed2000

Effects of Triatoma virus (TrV) on the fecundity and moulting of Triatoma infestans (Hemiptera: Reduviidae).

Triatoma virus (TrV) is a Picorna-like virus affecting Triatoma infestans (Klug, 1834), the most important transmitter of Trypanosoma cruzi in South America. The subjects of the present, laboratory study were the longevity and oviposition of female Tri. infestans, from stocks with and without viral infection, and the survivorship and developmental time of their progeny through to second-instar nymphs. On average, adult females from an infected stock lived only a third as long as those from the uninfected, and the mean monthly egg outputs of the 'infected' females was only 20% of that of the uninfected females. Even though the virus can be transmitted transovarially and most, if not all, of the progeny of the infected females were themselves infected, there was no evidence for TrV affecting egg hatchability. A much smaller proportion of the progeny of the females from infected stock than of that of the uninfected females successfully moulted to second-instar nymphs (44% v. 80%); the virus appears to inhibit the moulting process. The progeny of the females from the infected stock developed relatively slowly, spending a mean of 6.1 days as first instars (compared with 3.9 days for the progeny of uninfected females). Together, these data indicate that TrV may be a useful agent for the biological control of Tri. infestans.

Animals↗
PubMed1998

Experimental control of the schistosome-transmitting snail Biomphalaria pfeifferi by the ampullariid snail Pila ovata.

Adults of the African ampullariid snail Pila ovata were examined for their ability to control laboratory populations of the pulmonate snail Biomphalaria pfeifferi, a widespread, intermediate host of the human pathogen Schistosoma mansoni in sub-Saharan Africa. In a 6-week experiment conducted in large (100 x 60 x 60 cm) outdoor tanks containing floating macrophytes (Nymphaea caerula) and initially set up with one adult ampullariid for every three adult pulmonates, the numbers of B. pfeifferi egg masses were always about half those in similar tanks without P. ovata. Although, by week 6, the numbers of B. pfeifferi in the control tanks (without ampullariids) had increased 5-fold, from an initial mean of 30 snails/tank, there was no significant increase in the numbers of B. pfeifferi in the experimental tanks (containing ampullariids). Results of experiments conducted in indoor glass aquaria indicated that adult P. ovata rapidly attacked egg masses or neonates (< 2.5 mm shell diameter) of B. pfeifferi but had no effect on the adults. The adult ampullariids also significantly decreased cover by floating macrophytes over a 6-week period compared with that in similar but ampullariid-free aquaria. This decrease in plant cover is relevant to biological control of the schistosome vectors as macrophytes serve as food, shelter and oviposition sites for pulmonate snails. The present result indicate the ability of P. ovata to inhibit multiplication of B. pfeifferi populations, at least under laboratory conditions, both directly, through predation, and indirectly, by competition for resources. Pila ovata may therefore prove useful in the biological control of medically important, pulmonate snails.

Animals↗
PubMed1989

Natural control of larval Anopheles albimanus (Diptera: Culicidae) by the predator Mesocyclops (Copepoda: Cyclopoida).

Forty-two ground water sites on the Pacific and Atlantic coasts of Colombia were sampled quantitatively with a plankton net to assess the abundance of mosquito larvae and associated fauna. Many of the sites contained substantial numbers of Anopheles albimanus Wiedemann larvae, but the larvae were virtually absent wherever there were large populations of the copepods Mesocyclops venezolanus, M. longisetus, or M. aspericornis. Mesocyclops were observed to prey readily upon first-instar An. albimanus larvae in the laboratory, but smaller genera of cyclopoid copepods did not kill An. albimanus larvae. We conclude that Mesocyclops may prove useful for biological control of Anopheles.

Animals↗
PubMed1997

Reduction of mosquito larval densities in natural sites after introduction of Romanomermis culicivorax (Nematoda:Mermithidae) in Cuba.

Romanomermis culicivorax Ross & Smith became established in 4 of 6 treated sites and produced high levels of infection in Anopheles albimanus Wiedemann, Culex atratus Theobald, Psorophora confinnis Lynch-Arribálzaga, and Uranotaenia sapphirina Oster-Sacken mosquitoes for 9 wk in 1993. Mean levels of southern house mosquito parasitism ranged from 82 to 83% for Culex quinquefasciatus Say, at 2 sites, from 89 to 95% for An. albimanus at 4 sites, and from 78 to 80% at 2 sites for Cx. atratus, Ps. confinnis, and Un. sapphirina. Results indicated that R. culicivorax has potential use as biological control agent against mosquitoes in several different habitats in Cuba.

Animals↗
PubMed1990

Bait-fed adult Culex pipiens carry the larvicide Bacillus sphaericus to the larval habitat.

Sugar meals of plant origin are a basic component of mosquito diet. We show that sugar baits have potential as vehicles for control agents. When Culex pipiens L. resting-sites were sprayed with sucrose solution, with or without incorporation of the larval toxicant Bacillus sphaericus Neide, 47% of female mosquitoes fed in situ. Dispersing B. sphaericus-carrier mosquitoes caused larval mortality in breeding-sites 60-100 m from the sprayed resting-sites. The effect was not seen where no adults rested in sparse vegetation above larval habitats. This approach may be useful for the application of biological control agents against mosquitoes in biotopes where the adults and larvae are juxtaposed.

Aerosols↗
PubMed2000

Colonization of corn, Zea mays, by the entomopathogenic fungus Beauveria bassiana.

Light and electron microscopy were used to describe the mode of penetration by the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin into corn, Zea mays L. After inoculation with a foliar spray of conidia, germinating hyphae grew randomly across the leaf surface. Often a germ tube formed from a conidium and elongated only a short distance before terminating its growth. Not all developing hyphae on the leaf surface penetrated the cuticle. However, when penetration did occur, the penetration site(s) was randomly located, indicating that B. bassiana does not require specific topographic signals at an appropriate entry site as do some phytopathogenic fungi. Long hyphal structures were observed to follow the leaf apoplast in any direction from the point of penetration. A few hyphae were observed within xylem elements. Because vascular bundles are interconnected throughout the corn plant, this may explain how B. bassiana travels within the plant and ultimately provides overall insecticidal protection. Virulency bioassays demonstrate that B. bassiana does not lose virulence toward the European corn borer, Ostrinia nubilalis (Hübner), once it colonizes corn. This endophytic relationship between an entomopathogenic fungus and a plant suggests possibilities for biological control, including the use of indigenous fungal inocula as insecticides.

Animals↗
PubMed2002

Quantification in soil and the rhizosphere of the nematophagous fungus Verticillium chlamydosporium by competitive PCR and comparison with selective plating.

A competitive PCR (cPCR) assay was developed to quantify the nematophagous fungus Verticillium chlamydosporium in soil. A gamma-irradiated soil was seeded with different numbers of chlamydospores from V. chlamydosporium isolate 10, and samples were obtained at time intervals of up to 8 weeks. Samples were analyzed by cPCR and by plating onto a semiselective medium. The results suggested that saprophytic V. chlamydosporium growth did occur in soil and that the two methods detected different phases of growth. The first stage of growth, DNA replication, was demonstrated by the rapid increase in cPCR estimates, and the presumed carrying capacity (PCC) of the soil was reached after only 1 week of incubation. The second stage, an increase in fungal propagules presumably due to cell division, sporulation, and hyphal fragmentation, was indicated by a less rapid increase in CFU, and 3 weeks was required to reach the PCC. Experiments with field soil revealed that saprophytic fungal growth was limited, presumably due to competition from the indigenous soil microflora, and that the PCR results were less variable than the equivalent plate count results. In addition, the limit of detection of V. chlamydosporium in field soil was lower than that in gamma-irradiated soil, suggesting that there was a background population of the fungus in the field, although the level was below the limit of detection. Tomatoes were infected with the root knot nematode (RKN) or the potato cyst nematode (PCN) along with a PCN-derived isolate of the fungus (V. chlamydosporium isolate Jersey). Increases in fungal growth were observed in the rhizosphere of PCN-infested plants but not in the rhizosphere of RKN-infested plants after 14 weeks using cPCR. In this paper we describe for the first time PCR-based quantification of a fungal biological control agent for nematodes in soil and the rhizosphere, and we provide evidence for nematode host specificity that is highly relevant to the biological control efficacy of this fungus.

Animals↗
PubMed2003

Internal and external mycoflora of the American dog tick, Dermacentor variabilis (Acari: Ixodidae), and its ecological implications.

Scopulariopsis brevicaulis, the anamorph of Microascus brevicaulis (Microascaceae, Ascomycota), has been identified in the body contents of the tick Dermacentor variabilis. After topical application of the fungal inoculum, tick mortality was marked. This is the first account describing the internal mycoflora of D. variabilis with a novel technique used to recover potential biological control agents.

Animals↗
PubMed2002

Water activity, temperature, and pH effects on growth of the biocontrol agent Pantoea agglomerans CPA-2.

The growth response of the biocontrol agent Pantoea agglomerans to changes in water activity (a(w)), temperature, and pH was determined in vitro in nutrient yeast extract-sucrose medium. The minimum temperature at which P. agglomerans was able to grow was 267-272 kelvins (-6 to -1 degrees C), and growth of P. agglomerans did not change at varying pH levels (4.5-8.6). The minimum a(w) for growth was 0.96 in media modified with glycerol and 0.95 in media modified with NaCl or glucose. Solute used to reduce water activity had a great influence on bacterial growth, especially at unfavourable conditions (e.g., low pH or temperature). NaCl stimulated bacterial growth under optimum temperatures but inhibited it under unfavourable pH conditions (4.5 or 8.6). In contrast, the presence of glucose in the medium allowed P. agglomerans to grow over a broad range of temperature (3-42 degrees C) or pH (5-8.6) regimes. This study has defined the range of environmental conditions (a(w), pH, and temperature) over which the bacteria may be developed for biological control of postharvest diseases.

Biomass↗
PubMed2005

Biological control of apple blue mold with Pseudomonas fluorescens.

Pseudomonas fluorescens isolate 1100-6 was evaluated as a potential biological control agent for apple blue mold caused by Penicillium expansum or Penicillium solitum. Both the wild-type isolate 1100-6 and a genetically modified derivative labeled with the gene encoding the green fluorescent protein (GFP) were compared. The P. fluorescens isolates with or without GFP equally reduced the growth of Penicillium spp. and produced large zones of inhibition in dual culture plate assays. Cell-free metabolites produced by the bacterial antagonists reduced the colony area of Penicillium isolates by 17.3% to 78.5%. The effect of iron chelate on the antagonistic potential of P. fluorescens was also studied. The use of iron chelate did not have a major effect on the antagonistic activity of P. fluorescens. With or without GFP, P. fluorescens significantly reduced the severity and incidence of apple decay by 2 P. expansum isolates after 11 d at 20 degrees C and by P. expansum and P. solitum after 25 d at 5 degrees C when the biocontrol agents were applied in wounds 24 or 48 h before challenging with Penicillium spp. Populations of P. fluorescens labeled with the GFP were determined 1, 9, 14, and 20 d after inoculation at 5 degrees C. The log CFU/mL per wound increased from 6.95 at the time of inoculation to 9.12 CFU/mL (P < 0.05) 25 d after inoculation at 5 degrees C. The GFP strain did not appear to penetrate deeply into wounds based on digital photographs taken with an inverted fluorescence microscope. These results indicate that P. fluorescens isolate 1100-6 could be an important new biological control for apple blue mold.

Green Fluorescent Proteins↗
PubMed2004

Foraging behavior and prey interactions by a guild of predators on various lifestages of Bemisia tabaci.

The sweetpotato whitefly, Bemisia tabaci (Gennadius) is fed on by a wide variety of generalist predators, but there is little information on these predator-prey interactions. A laboratory investigation was conducted to quantify the foraging behavior of the adults of five common whitefly predators presented with a surfeit of whitefly eggs, nymphs, and adults. The beetles, Hippodamia convergens Guerin-Meneville and Collops vittatus (Say) fed mostly on whitefly eggs, but readily and rapidly preyed on all of the whitefly lifestages. The true bugs, Geocoris punctipes (Say) and Orius tristicolor (Say) preyed almost exclusively on adult whiteflies, while Lygus hesperus Knight preyed almost exclusively on nymphs. The true bugs had much longer prey handling times than the beetles and spent much more of their time feeding (35-42%) than the beetles (6-7%). These results indicate that generalist predators vary significantly in their interaction with this host, and that foraging behavior should be considered during development of a predator-based biological control program for B. tabaci.

Animals↗
PubMed2005

The Oryctes virus: its detection, identification, and implementation in biological control of the coconut palm rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae).

In view of the increasing and devastating damage by rhinoceros beetle (Oryctes rhinoceros) to coconut palms in the middle of last century, many efforts were made to find an efficient natural control factor against this pest, which could not be controlled by pesticides. The basic procedures of these monitoring programmes are outlined together with the final detection of a virus disease in oil palm estates in Malaysia in 1963. In extensive laboratory studies, the virus was isolated and identified as the first non-occluded, rod-shaped insect virus, morphologically resembling the baculoviruses. Infection experiments clarified the pathology, histopathology, and virulence of the virus and demonstrated that the virus was extremely virulent to larvae after peroral application. These findings encouraged the first pilot release of virus in 1967 in coconut plantations of Western Samoa where breeding sites were contaminated with virus. Surprisingly, the virus became established in the Samoan rhinoceros beetle populations and spread autonomously throughout the Western Samoan islands. As a consequence, there was a drastic decline of the beetle populations followed by a conspicuous recovery of the badly damaged coconut stands. This unexpected phenomenon could only be explained after it was shown that the adult beetle itself is a very active virus vector and thus was responsible for the efficient autodissemination of the virus. The functioning of the beetle as a 'flying virus factory' is due to the unique cytopathic process developing in the midgut after peroral virus infection. Pathological details of this process are presented. Because of the long-term persistence of the virus in the populations, rhinoceros beetle control is maintained. Incorporation of virus into integrated control measures and successful virus releases in many other countries are recorded.

Animals↗
PubMedDate not supplied

The use of baculoviruses as expression vectors.

The use of recombinant baculoviruses as high level expression systems is becoming more and more popular. This review aims to provide a summary of the impact of this expression system in biochemistry and biotechnology, highlighting important advances that have been made utilizing the system. The potential of newly developed multiple baculovirus expression systems to enable the reconstruction of complex biological molecules and processes is also reviewed.

Animals↗