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PubMed1990

Commercial and naturally occurring fly parasitoids (Hymenoptera: Pteromalidae) as biological control agents of stable flies and house flies (Diptera: Muscidae) on California dairies.

Filth fly parasites reared by commercial insectaries were released on two dairies (MO, DG) in southern California to determine their effect on populations of house flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.). Spalangia endius Walker, Muscidifurax raptorellus Kogan and Legner, and Muscidifurax zaraptor Kogan and Legner were released on the MO dairy from 1985 to 1987 in varying quantities. Parasitism by Muscidifurax zaraptor on the MO dairy was significantly higher (P less than 0.05) from the field-collected stable fly (4.4%) and house fly (12.5%) pupae, compared with a control dairy (0.1%, stable fly; 1.3%, house fly). Muscidifurax zaraptor, released from April through October during 1987 on the DG dairy (350,000 per month), was not recovered in a significantly higher proportion from either fly species relative to the corresponding control dairy. No specimens of Muscidifurax raptorellus were recovered from the MO dairy. Parasite treatments had no apparent effect on adult populations of either fly species or on overall parasitism rate of field-collected stable fly (16.8%, MO; 17.2%, DG) and house fly (23.3%, MO; 20.9%, DG) pupae. Spalangia spp. were the predominant parasites recovered from field-collected stable fly and house fly pupae on all four dairies. Sentinel house fly pupae placed in fly-breeding sites on both release dairies were parasitized at a significantly higher rate, as compared with sentinel pupae on control dairies. The generic composition of parasites emerging from sentinel house fly pupae was 20.6% Spalangia spp. and 73.2% Muscidifurax spp., whereas in field-collected house fly pupae, Spalangia spp. and Muscidifurax spp. constituted 74.3 and 19.6% of the parasites, respectively.

Animals↗
PubMed1999

A new isolate of the nematophagous fungus Duddingtonia flagrans a biological control agent against free-living larvae of horse strongyles.

An experiment was carried out in 1997 to test the efficacy of an isolate of the microfungus Duddingtonia flagrans against free-living stages of horse strongyles under conditions in the field and to assess the eventual effect of the fungus on the normal degradation of faeces. Faecal pats were made from faeces of a naturally strongyle infected horse, which had been fed fungal material at a dose level of 106 fungal unit/kg bwt. Control pats without fungi were made from faeces collected from the same animal just before being fed fungi. Faecal cultures set up for both groups of faeces to monitor the activity of the fungus under laboratory conditions showed that the fungus significantly reduced the number of infective third-stage larvae (L3) by an average of 98.4%. Five faecal pats from each batch of faeces were deposited on pasture plots at 3 times during spring-summer. The herbage around each pat was sampled fortnightly to recover L3 transmitted from faeces. The results showed that the herbage infectivity around fungus-treated pats was reduced by 85.8-99.4%. The remaining faecal material at the end of each sampling period was collected, and the surviving L3 were extracted. Significantly fewer larvae were recovered from the fungus-treated pats. Analysis of wet and dry weight of the collected pats, as well as their organic matter content, were performed to compare the degradation of faeces of both groups. The results indicated that the presence of the fungus did not alter the degradation of the faeces.

Animal Feed↗
PubMed2001

Fate of the biological control agent Pseudomonas aureofaciens TX-1 after application to turfgrass.

The fate and impact of Pseudomonas aureofaciens TX-1 following application as a biocontrol agent for fungi in turfgrass were studied. The organism was applied with a modified irrigation system by using a preparation containing 1 x 10(6) P. aureofaciens TX-1 CFU ml(-1) about 100 times between May and August. We examined the impact of this repeated introduction of P. aureofaciens TX-1 (which is known to produce the antimicrobial compound phenazine-1-carboxylic acid) on the indigenous microbial community of the turfgrass system and on establishment of introduced bacteria in the soil system. A PCR primer-DNA hybridization probe combination was developed to accurately monitor the fate of P. aureofaciens TX-1 following application in irrigation water. To assess the impact of frequent P. aureofaciens TX-1 applications on the indigenous bacterial community, turfgrass canopy, thatch, and rhizosphere samples were obtained during the growing season from control and treated plots and subjected to DNA extraction procedures and denaturing gradient gel electrophoresis (DGGE). PCR amplification and hybridization of extracted DNA with the P. aureofaciens TX-1-specific primer-probe combination revealed that P. aureofaciens TX-1 not only became established in the rhizosphere and thatch but also was capable of overwintering. Separation of PCR-amplified partial 16S rRNA genes by DGGE showed that the repeated application of P. aureofaciens TX-1 in irrigation water resulted in transient displacement of a leaf surface bacterial community member. There was no obvious alteration of any dominant members of the thatch and rhizosphere microbial communities.

DNA, Ribosomal↗
PubMed2000

National progress in dengue vector control in Vietnam: survey for Mesocyclops (Copepoda), Micronecta (Corixidae), and fish as biological control agents.

This paper describes the process of expanding a successful dengue control program in 3 provinces in northern Vietnam into a national one and demonstrates the presence of a rich, low-cost resource that could have similar applicability to other countries in the region. The cornerstone of the preventive strategy is larval control of Aedes aegypti (L.), the major vector, using predators such as copepods, Mesocyclops spp., aided by the corixid bug Micronecta quadristrigata Bredd, and fish in large water storage containers. From 1989 to 1998, 9 species of Mesocyclops (M. woutersi Van de Velde, M. aspericornis (Daday), M. ruttneri Kiefer, M. thermocyclopoides Harada, M. affinis Van de Velde, M. ogunnus Onabamiro, M. yenae Holynska, M. cf. pehpeiensis Hu, and M. dissimilis Defaye and Kawabata) were found in natural and artificial habitats in 26 provinces throughout Vietnam. The predatory capacities of 6 of these were evaluated in the laboratory. This indicated that daily consumption/killing averaged between 16 and 41 Ae. aegypti larvae per copepod. From detailed evaluations in 9 provinces, Mesocyclops spp. were surprisingly common in 8,413 artificial containers (concrete tanks, wells, ornamental ponds and in the south, large jars). Because of existing practices for washing and water transfer from ponds and lakes in Ha Tay and Ha Bac, Mesocyclops spp. already occurred in 60-100% of the water storage containers. When the relationship between the presence or absence of Mesocyclops and Aedes larvae in 5,111 containers was analyzed by the chi-square test, their distributions were significantly related, indicating control (odds ratio = 0.56). When 3,426 containers that did not contain Mesocyclops or fish were analyzed in relation to the distribution of Aedes larvae, those with Micronecta also had significantly less Aedes (odds ratio = 0.43). Therefore, this study demonstrates that there is an abundance of local Mesocyclops spp. in Vietnam that can be incorporated into specifically designed community-based control programs aided by Micronecta and fish.

Aedes↗
PubMed2005

Development of real-time PCR using Minor Groove Binding probe to monitor the biological control agent Candida oleophila (strain O).

A real-time PCR assay using a 3'-Minor Groove Binding (MGB) probe was developed for specific detection and monitoring of Candida oleophila (strain O), a biocontrol agent against Botrytis cinerea and Penicillium expansum, on harvested apples. The application of the RAPD technique on C. oleophila strains followed by reproducible sequence characterized amplified region (SCAR) amplifications allowed the identification of a semi-specific fragment of 244 bp, observed in the profiles of strain O and three other C. oleophila strains. After sequencing, polymorphisms (3%) were observed between the strain O sequence and the three other sequences. A 3'-Minor Groove Binding probe was designed to specifically match a region of the strain O sequence and was able to discriminate a single base mutation or a two-base difference in the corresponding sequences of the non-target strains. This specific detection method was applied to monitor strain O population, recovered by a washing buffer, from harvested apples. Population densities were calculated using an external standard curve consisting in a serial dilution of strain O cells in the washing buffer from untreated apples. Linearity in the standard curve was kept between 1.64 x 10(2) and 1.64 x 10(5) cfu cm(-2) of apple surface. During a first practical experiment, the calculated population densities were similar to those obtained by plating on semi-selective media. This new real-time PCR method is a promising tool to monitor quickly and specifically strain O population on apple surface in middle- or large-scale experiments.

Candida↗
PubMed2004

Susceptibility of the leaf-eating beetle, Galerucella calmariensis, a biological control agent for purple loosestrife (Lythrum salcaria), to three mosquito control larvicides.

We evaluated the susceptibility of Galerucella calmariensis, a species used to control purple loosestrife (Lythrum salicaria), to three mosquito control larvicides. Larvae and adults were fed loosestrife cuttings dipped in Abate (< or = 375 g x L(-1)), Altosid (< or = 250 g x L(-1)), and Bacillus thuringiensis var israeliensis (Bti) (< or = 110 g x L(-1)). Eggs on cuttings were dipped in the same concentrations. Pupae were immersed in Abate and Altosid solutions (< or = 474.4 microg x L(-1) and < or = 1,169.2 microg x L(-1), respectively). Hatching success of eggs dipped in Abate (> or = 3.75 g x L(-1)) was reduced significantly and survival was significantly lower among larvae and adults eating cuttings dipped in Abate (> or = 0.17 g x L(-1) and > or = 2.27 g x L(-1), respectively). Hatching success of eggs dipped in Altosid (> or = 2.52 g x L(-1)) was reduced significantly. With exposure to Altosid, larval survival to pupation and adult emergence was reduced significantly at concentrations of > or = 2.92 g x L(-1) and > or = 0.63 g x L(-1), respectively. Altosid (> or = 0.23 g x L(-1)) also delayed the onset of pupation and adult emergence among larvae that survived to pupate. Larvae that survived with exposure to Altosid (> or = 1.72 g x L(-1)) grew to 70% larger than those exposed to lower concentrations. Pupal survival was unaffected with exposure to Abate and Altosid and adult survival was unaffected with exposure to Altosid. Bacillus thuringiensis var israeliensis did not adversely affect any life stage of G. calmariensis. The mean Abate concentration on cuttings exposed to operational spraying was in the range that reduced egg hatchability and adult survival but was higher than concentrations that caused complete mortality of larvae. The mean Altosid concentration on cuttings exposed to operational spraying was in the range that reduced hatching success in eggs and delayed pupation and adult emergence of larvae.

Animals↗
PubMed1986

A field evaluation of Bacillus thuringiensis var. israelensis as a biological control agent for Simulium chutteri (Diptera:Nematocera) in the middle Orange River.

Bacillus thuringiensis Berliner var. israelensis de Barjac (Serotype H-14) (B.t.i.) at a concentration of 1.6 ppm/10 min and a toxicity of 1500 AAU/mg was tested against Simulium chutteri Lewis larvae in the Orange River near Prieska, South Africa. Samples of benthic fauna from the stones-in-current biotope were collected before application of the product and at various intervals up to 80 h afterwards at 4 stations from 200 m to 11 km downstream of the application site. Fauna drift increased slightly after the arrival of the Bacillus at 2 stations 1.4 and 6 km respectively downstream of the application site. Large numerical decreases in benthic simuliid larval numbers after the application of B.t.i. in the Orange River were not statistically different (P greater than 0.05). This indicated that the size of replicated samples that showed significant decreases (P less than 0.05) of simuliid numbers in the Vaal River was not adequate to show statistical differences in the Orange River. The quantity of dead larvae on stones collected from rapids after application of the B.t.i., and the numerical decreases found by comparing median values of larval counts on stones indicated that B.t.i. effectively killed simuliid larvae. Three days after application of the Bacillus, recruitment of small simuliid larvae on stones 1.4 km downstream of the application site was discernible again. Tanytarsini were also numerically reduced after B.t.i. application. At a flow rate of 38 m3/s B.t.i. was visibly effective in killing S. chutteri up to 6 km downstream of the application site and statistically significant decreases (P less than 0.05) in numbers of larvae were seen at a site 11 km downstream of the application site.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Evaluating the effectiveness of a Mexican strain of Duddingtonia flagrans as a biological control agent against gastrointestinal nematodes in goat faeces.

The use of Duddingtonia flagrans in the control of goat nematodes was investigated. Initially, the time of passage of chlamydospores through the digestive tract of goats was evaluated. Two groups of seven parasite-free kids were formed. Group A received a single dose of 3.5x10(6) D. flagrans chlamydospores (FTHO-8 strain) per kg of live weight. Group B did not receive any chlamydospores. Faeces were obtained from each kid daily from day 4 prior to inoculation until day 5 post-inoculation (PI) and were placed in Petri dishes containing water agar. Gastrointestinal nematode infective larvae were added to each Petri dish and incubated at 25 degrees C for 7 days. Petri dishes were examined to detect the fungus and trapped nematodes. A second trial evaluated the effect of D. flagrans on the number of gastrointestinal nematode larvae harvested from goat faecal cultures in naturally infected goats. Two groups of seven goats were formed. The treated group received a single dose of 3.5x10(6) D. flagrans chlamydospores per kg of liveweight. The control group did not receive any chlamydospores. Faeces were obtained twice daily from each kid. Two faecal cultures were made for each kid. One was incubated for 7 days and the other for 14 days. Gastrointestinal nematode larvae were recovered from each culture and counted. Percentage of larval development reduction was determined using a ratio of larvae/eggs deposited in the control and treated groups. Duddingtonia flagrans survived the digestive process of goats, and maintained its predatory activity, being observed from 21 to 81 h PI (3 to 4 days). A reduction in the infective larvae population in the treated group compared to the non-treated group was observed in both incubation periods (7 days: 5.3-36.0%; 14 days: 0-52.8%, P>0.05). Although a single inoculation of D. flagrans can induce a reduction of infective larvae collected from faeces, a different scheme of dosing may be needed to enhance the efficacy of D. flagrans in goats.

Animals↗
PubMed1994

Pyrrolnitrin Production by Biological Control Agent Pseudomonas cepacia B37w in Culture and in Colonized Wounds of Potatoes.

Bacterial strain B37w (= NRRL B-14858), an isolate noteworthy because it inhibits the growth of the bioherbicide fungus Colletotrichum truncatum, was selected for further studies of bacterial antifungal properties. This isolate was identified as a Pseudomonas cepacia strain by performing carbohydrate utilization and fatty acid profile analyses, as well as other biochemical and physiological tests. Petri plate assays revealed that strain B37w exhibited antifungal activity against the potato dry rot fungus Fusarium sambucinum. Using bioautography, we correlated antifungal activity with production of a specific compound. Isolation from strain B37w and identification of the antifungal antibiotic pyrrolnitrin are described. A whole-potato assay revealed B37w's ability to colonize potato wounds. Wounded potatoes were inoculated with B37w, and pyrrolnitrin was detected in these potatoes by thin-layer chromatography-bioautography at a concentration on the order of nanograms per wound. We performed an assay in which we examined efficacy against F. sambucinum-incited potato dry rot and found that B37w inhibited disease development. This is the first report of P. cepacia or pyrrolnitrin activity against the economically important potato pathogen F. sambucinum.

Journal Article↗
PubMed2003

Evaluation of a select strain of Lactobacillus delbrueckii subsp. lactis as a biological control agent for pathogens on fresh-cut vegetables stored at 7 degrees C.

Raw vegetables inoculated with selected pathogenic bacteria were treated with a strain of Lactobacillus delbrueckii subsp. lactis, which was selected for its ability to produce hydrogen peroxide at refrigerated temperatures. The vegetables inoculated included broccoli, cabbage, carrots, and lettuce. Each vegetable was rinsed, chopped, and stored under conditions similar to those used for ready-to-eat vegetables sold at retail. Portions of each vegetable were separately inoculated with one of two pathogenic bacteria, Escherichia coli O157:H7 or Listeria monocytogenes. Prior to packaging, one portion of each inoculated vegetable was treated with a cell suspension of the selected strain of L. delbrueckii subsp. lactis. The vegetables were stored at 7 degrees C for 6 days. The populations of pathogens and lactobacilli on each sample were enumerated on storage days 0, 3, and 6. Although populations of L. delbrueckii subsp. lactis remained at high levels during storage, there was no noticeable antagonistic action against the pathogens under conditions similar to those used for these products at the retail level. Each pathogen survived on all vegetables throughout storage. Further testing revealed that there was apparently sufficient catalase activity in the cut vegetables to destroy enough of the hydrogen peroxide to prevent antagonistic action against the pathogens.

Colony Count, Microbial↗
PubMed2001

Effects of nutritional factors and soil addition on growth, longevity and fecundity of the tadpole shrimp Triops newberryi (Notostraca: Triopsidae), a potential biological control agent of immature mosquitoes.

The notostracan tadpole shrimp (TPS) Triops newberryi Packard has potential to be used as a biocontrol agent of immature mosquitoes. Eggs, nymphal or adult shrimps are considered to be the stages for field introduction. To yield good growth of the shrimp and high production of shrimp eggs under artificial conditions, nutritional requirements of TPS for growth, survival and fecundity need to be elucidated. In the laboratory, we evaluated various nutritional and edaphic regimens, such as soil alone, mosquito larvae or rabbit pellets alone and various combinations of these three components for culturing. These factors influenced the growth, longevity and egg production profoundly. It was shown that the simulated natural conditions, i.e. full combination of all three factors, yielded the largest TPS with longest survival and highest egg production, followed by the combinations of any two components. Any single component, soil, mosquito larvae, or rabbit pellets, did not result in good growth, survival and egg production. By formulating optimal rearing substrates, this species of TPS will yield large numbers of all stages for experimentation and field introductions. Under optimal conditions, they mature in 7-8 days and survive for about one month. Each TPS is capable of producing up to 1,000 eggs during its lifetime. These studies developed nutritional regimens for TPS mass culturing procedures, where the eggs, nymphal and adult TPS can be mass cultured for field introduction and stocking in mosquito developmental sites.

Animal Feed↗
PubMed2001

Application of Bacillus thuringiensis in poultry houses as a biological control agent against the housefly, Musca domestica sorbens.

The efficiency of Bacillus thuringiensis (B.t) as a microbial housefly control agent was evaluated in one of the natural maggot breeding medium, namely poultry faeces. Two commercial formulations, a wettable powder and a liquid concentrate were assayed against Musca domestica sorbens in synthetic fly breeding madia and in chicken faeces. The latter was found to favour maggot breeding when compared with the synthetic one. Both formulations resulted in significant reduction in maggot numbers,, pupal development and adult emergence. Concentration was found significantly affecting adult emergence. The liquid concentrate induced higher larvicidal activity than dry powder formulation. Contaminated faeces produced from orally fed chickens were found significantly toxic to the breeding maggots, reaching maximum larvicidal activity till the 4th day post-feeding faeces, and continued in less activity till the 6th day. Adding B.t. in chicken food in poultry mass breeding is recommended for housefly control.

Animal Husbandry↗
PubMed1995

Biocontrol from a mosquito control director's point of view.

Two principal mosquito breeding problems that occur in Florida are discussed from the standpoint of a manager of a mosquito abatement district: 1) mosquitoes that breed in standing or permanent water, and 2) mosquitoes that breed in temporary habitats such as floodwater pools. The efficacies of several different types of biological control agents are discussed for each type of problem. Fish are used in permanent water sites, and several other organisms are being evaluated. No programs are based exclusively on biological control agents. Biological control is generally not used in temporary sites. Relative costs of chemical and biological control are discussed.

Animals↗
PubMed2004

Evaluation of a contraction flow field on hydrodynamic damage to entomopathogenic nematodes-A biological pest control agent.

Mechanized production and delivery of biological pesticides presents challenges because the biological agents must remain viable during these processes. This study evaluates the effect of flow through an abrupt contraction, where flow characteristics similar to that found within bioprocesses and spray equipment are developed, on damage to a benchmark biological pest control agent, entomopathogenic nematodes (EPNs). An opposed-pistons, contraction flow device generated volumetric flow rates ranging between 8.26 cm(3)/s and 41.3 cm(3)/s. Four EPN species were evaluated: Heterorhabditis bacteriophora, Heterorhabditis megidis, Steinernema carpocapsae, and Steinernema glaseri. Damage was quantified by counting living and dead EPNs. Optical and cold field emission scanning electron microscope (CFE-SEM) images provided qualitative information to describe how the damage occurred. The experimental flow field was completely described using FLUENT, a computational fluid dynamics program. Local flow parameters computed in FLUENT were compared to EPN damage. The type and extent of damage varied between EPN species. Damaged Heterorhabditis spp. generally remained whole with an internal rupture located near the center of the body, while Steinernema spp. most often broke into several pieces. The fast-transient stress field generated at the entrance to the contraction caused a momentary tensile loading and then relaxation that damaged the EPNs. At high flow rates, the tensile stresses became large enough to cause failure of the EPN structural membrane. The relative elasticity of the EPN structural membrane may explain the differences in damage observed between the species. It is speculated that the internal rupture of the Heterorhabditis spp. occurred during the processes of stretching and relaxing at the contraction entrance. Appreciable damage was observed at lower average energy dissipation rates for H. bacteriophora (1.23E + 8 W/m(3)), H. megidis (1.72E + 8 W/m(3)), and S. glaseri (2.89E + 8 W/m(3)) compared to S. carpocapsae (3.70E + 8 W/m(3)). Energy dissipation rates within an equipment component should be kept below 1E + 8 W/m(3) to avoid hydrodynamic damage to EPNs. The relationship between average energy dissipation and EPN damage provides important information for future simulation efforts of actual spray equipment components.

Animals↗
PubMed2005

Phylogeny of certain biocontrol agents with special reference to nematophagous fungi based on RAPd.

A number of phylogenetic studies have been carried out on biocontrol agents having similar biological control activity. However, no work has been carried out to determine the phylogenetic relationship amongst various groups of biological control agents with varied biocontrol properties. Our aim was to derive a phylogenetic relationship between diverse biocontrol agents belonging to the deuteromycetes and determine its correlation with their spore morphology and their biocontrol activity. RAPD was used to assess genomic variability in fungi used as biological control agents which included ten isolates of nematophagous fungi such as Arthrobotrys sp., Duddingtonia sp., Paecilomyces sp. and Verticillium sp., along with two isolates of fungal biocontrol agents such as Trichoderma sp. and two isolates of entomopathogenic fungi including Beauveria sp. A plant pathogenic fungus, Verticillium alboatrum was also included to increase the diversity of Deuteromycetes used. A similarity matrix was created using Jaccard's similarity coefficient & clustering was done using unweighted pair group arithmetic mean method (UPGMA). The final dendogram was created using a combination of two programs, Freetree and TreeExplorer. The phylogenetic tree constructed from the RAPD data showed marked genetic variability among different strains of the same species. The spore morphologies of all these fungi were also studied. The phylogenetic pattern could be correlated with the conidial and conidiophore morphology, a criterion commonly used for the classification of fungi in general and Deuteromycetes in particular. Interestingly, the inferred phylogeny showed no significant grouping based on either their biological control properties or the trapping structures amongst the nematophagous fungi as reported earlier by other workers. The phylogenetic pattern was also similar to the tree obtained by comparing the 18S rRNA sequences from the database. The result clearly indicates that the classical method of classification of these deuteromycete members on the basis of their spore morphology is reliable and could be used for identification of these fungi at species level. The PCR fragment pattern polymorphism exhibited by the various species of a genus and different strains of a species indicates that construction of probes from one or more of these fragments will prove to be useful as a rapid tool for identification of species and strains of nematophagous fungi in future.

Base Sequence↗
PubMed1997

The ciliate Orchitophrya cf. stellarum and other parasites and commensals of the northern Pacific seastar Asterias amurensis from Japan.

To identify the pathogens and possible biological control agents for the introduced seastar Asterias amurensis, we examined seastars from source populations in central and northern Japan. In particular, we sought the scuticociliate Orchitophrya cf. stellarum. The ciliate was found in male A. amurensis from five sites. We also found the caprellid amphipod Caprella astericola on A. amurensis and Distolasterias nipon from Nemuro Bay. The copepod Scottomyzon gibberum was found on A. amurensis from Usujiri and polychaete scaleworms Arctonoe vittata were found on A. amurensis from Murohama and Nemuro Bay. Of these parasites and commensals, Orchitophrya cf. stellarum is the most likely agent for biological control of A. amurensis in Australian waters; however, its ability to regulate seastar populations is uncertain.

Animals↗