Biocontrol of Phytophthora Root Rot of Angelica Trees by Enterobacter cloacae and Serratia ficaria Strains

Bacterial strains isolated from the rhizosphere of angelica trees were evaluated for their antagonistic activity against Phytophthora cactorum, a causal agent of Phytophthora root rot. Of these, three bacterial strains, designated as T-1-8, T-1-14 and T-1-23, strongly inhibited mycelial growth of P. cactorum ARE-862 in a dual-culture plate assay. Biocontrol activity of these strains was then examined by dipping root of young seedlings of angelica trees into a bacterial suspension. The incidence of Phytophthora root rot was markedly suppressed for at least 79 days in pot tests when treated seedlings were planted in naturally infested soil. The suppression was maintained through June of the next year. In addition, these strains significantly reduced the development of Phytophthora root rot up to 47 days in naturally infested field and up to 63 days (the last day of testing) in an artificially (moderately) infested field. Based on their main bacteriological properties, strain T-1-14 was identified as Enterobacter cloacae and T-1-8 and T-1-23 were identified as Serratia ficaria. Received 5 July 1999/ Accepted in revised form 25 October 1999     

Monitoring of <Emphasis Type="Italic">Phytophthora</Emphasis> species on fruit trees in Bulgaria

Disease on fruit trees in Bulgaria caused by Phytopthora cactorum and P. citrophthora was found in the period 1998–1999. Leaves of some trees become reddish during July, and later in the season fall off. Infected trees die during the same season, or the next season. Observations on symptom development and spread of Phytophthora root and crown rot of fruit trees was undertaken from 1999 to 2009. Disease incidence is between 2% and 14% in some gardens and nurseries. The disease was registered in the regions of Plovdiv, Kjustendil, Sliven, Yambol, Karnobat, Bourgas and Svishtov. Samples from infected plant tissues were taken and isolations were done on selective PARP media, or by applying a baiting bioassay. Based on morphological and cultural characteristics and temperature requirements the following Phytophthora species have been identified: Phytophthora cactorum, P. citrophthora, P. drechsleri, P. cryptogea, hybrid and Pythium. Pathogenicity of the isolates was tested on green apple fruits or one-year-old apple rootstocks. Laboratory studies of the effect of temperature on mycelia growth showed that most isolates can grow from 5° up to 30°C, with an optimum from 18° to 25°C. Only three strains grew at 35–36°C, two developed slowly, one grew well. The optimal pH for mycelia development was tested. Aiming at control of disease, in vivo pot trials have been carried out for studying resistance of rootstocks to P. cactorum. At the end of the growing season a good level of resistance has been shown in the rootstocks M29C, Gizela 6, and MAXMA 14.     

除草剂对小麦田雀麦的生物活性测定

为筛选防除雀麦Bromus japonicus的高效除草剂,采用室内生物测定法研究了13种除草剂对雀麦的除草活性及5种除草剂的田间药效试验。结果表明,在田间推荐剂量的低剂量下,氟唑磺隆、啶磺草胺、氟噻草胺、甲基二磺隆、异丙隆、磺酰磺隆、丙苯磺隆7种除草剂对雀麦具有很高的防除效果,21 d鲜重抑制率分别为88.30%、86.32%、83.97%、78.47%、76.76%、72.83%、71.39%,高剂量下的21 d鲜重抑制率达98.57%、95.36%、91.58%、91.46%、89.47%、82.48%、82.20%;其中氟唑磺隆各剂量下的防效较其它除草剂高。而嘧啶肟草醚、苯唑草酮、炔草酯、吡氟酰草胺、唑啉草酯、精噁唑禾草灵6种除草剂对雀麦防效较差。氟唑磺隆、啶磺草胺、氟噻草胺、甲基二磺隆、异丙隆5种除草剂的田间药效试验表明,氟唑磺隆对雀麦防效最高,高剂量下20 d株防效达85.04%,药后40 d株防效和鲜重防效分别达83.94%和84.17%,未见小麦有明显药害症状,建议田间推荐用量为21.00~42.00 g(a.i.)/hm~2。表明雀麦对不同除草剂的敏感性存在差异,在供试的13种除草剂中氟唑磺隆对雀麦防效最高,较为安全,为防除雀麦的理想除草剂。     

酵母菌0732-1产生的抑细菌物质特性研究

<正>哈密瓜细菌性果斑病是近年来暴发流行的一种瓜类病害,也是我国对内对外检疫性重大植物病害。该病由燕麦嗜酸菌西瓜亚种(Acidovorax avenae subsp.citrulli,Aac)引起,具有发病快、危害广、损失重、防治难的特点,一旦发生往往给瓜产区造成严重经济损失。据报道[1],2007年新疆石河子市温室栽培的西瓜叶片上曾获得一株对Aac有     

Effects of certain herbicides on the fate of sporangiospores of Mucor piriformis and conidia of Botrytis cinerea and Penicillium expansum

The effects of several herbicides used in pome fruit orchards on the germination of spores and growth of mycelia of Botrytis cinerea, Mucor piriformis and Penicillium expansum in vitro and the survival of propagules of these fungi in soil were studied. Diuron in agar at 4–128 μg ml^?1 reduced germination of spores of B. cinerea and M. piriformis, and 2,4-D and paraquat at 32 μg ml^?1 similarly affected B. cinerea and P. expansum. Several herbicides at 128 μg ml^?1 in agar reduced growth of B. cinerea and M. piriformis but were ineffective against P. expansum. Propagule survival levels of the three fungi generally were lower in both autoclaved and non-autoclaved soil amended with herbicides than in non-amended soil. This effect was greatest in non-autoclaved soil, suggesting involvement of microbial antagonists. The most effective herbicides for reduction of fungal propagules in soil were 2,4-D, diuron, and paraquat.     

Efficacy of some rhizospheric and endophytic bacteria <Emphasis Type="Italic">in vitro</Emphasis> and as seed coating for the control of <Emphasis Type="Italic">Fusarium culmorum</Emphasis> infecting durum wheat in Tunisia

Sixty two rhizospheric and endophytic bacterial strains were evaluated for their biocontrol effect on two aggressive Fusarium culmorum isolates (Fc2 and Fc3). We observed that 35 % and 23 % of the tested strains inhibited the in vitro growth of Fc2 and Fc3 respectively. The observed antagonism was due to inhibition by contact (13–19 % of the strains) or at distance (10–16 % of the strains) for both fungal isolates. Some of the antagonistic bacteria showed the ability to produce diffuse and/or volatile compounds that inhibit the growth, the sporulation and macroconidia germination of F. culmorum. None of the tested antagonistic bacteria showed chitinase activity on synthetic medium. The sequencing of the 16S rDNA genes of some antagonistic bacteria showed that they belong to the genera Bacillus, Pseudomonas and Microbacterium. The double inoculation of durum wheat seeds by the antagonistic bacterial strains (B13, B18, BSE1, BSE3 and B16E) and the two F. culmorum isolates showed that germination and seedling vigor were generally improved in vitro. The percentage of infected seeds was also reduced. In greenhouse trials, the biocontrol effectiveness of F. culmorum was dependant from the virulence of the fungal strain and the specificity of the antagonistic interaction between bacterial and fungal strains. The bacterial strains B18 and B16E reduced F. culmorum infection on durum wheat plants probably due to their antagonistic and plant growth promoting activities and they may be used in a mixture as seed biopriming inoculum for plant growth bio-promoting and Fusarium wheat diseases biocontrol.     

The influence of additives on the penetration of foliar applied growth regulator herbicides

The possibilities are demonstrated of increasing the activity of foliar applied growth regulator herbicides by mixing them with chemicals which injure the cuticle or epidermis. S, S, S-Tributyl phosphorotrithioate (“DEF”) increases the effects of picloram, 2,4,5-T and mecoprop salts on four woody species, privet (Ligustrum ovalifolium Hassk.), poplar (× Populus gelrica Ait.), bluegum (Eucalyptus globulus Labill.) and guava (Psidium guajava L.). Mixtures with esters of the herbicides are not synergistic and often antagonistic. DEF, tributyl phosphorotrithioite, a number of alkyl and aryl phosphates and phosphites and potassium ethyl xanthate enhance the phytotoxicity of picloram solution on dwarf bean (Phaseolus vulgaris L.). Mixtures of picloram with tributyl phosphorotrithioite, tributyl phosphate, mixed acid butyl phosphates, trimethyl phosphate and mixed isomers of tritolyl phosphate are synergistic when applied to guava foliage. Tributyl phosphate and mixed acid butyl phosphates interact similarly with picloram on privet and tributyl phosphate increases the effects of foliar applied mecoprop salt on guava. The mode of action of the additives is not fully understood but there is evidence that DEF facilitates the entry of water soluble growth regulator herbicides into leaves and has little effect on the rate at which the herbicides move through the plant. Tributyl phosphate and mixed acid butyl phosphates are suggested for practical use in herbicide formulations to control woody plants, as they are relatively cheap and non-toxic.     

Natural hybrids of resident and introduced <Emphasis Type="Italic">Phytophthora</Emphasis> species proliferating on multiple new hosts

Several atypical Phytophthora strains, isolated from a range of horticultural hosts, were tentatively identified as P. cactorum. Numerous abortive oospores were observed in these strains and isozyme analysis showed all were heterozygous for the dimeric malic enzyme (MDHP). More detailed comparisons indicated that their MDHP alleles matched those of both P. cactorum and P. hedraiandra. Cloning and sequencing of the nuclear ribosomal internal transcribed spacer (ITS) regions of the atypical P. cactorum strains demonstrated the presence of sequences characteristic for both P. cactorum and P. hedraiandra. It was concluded that the atypical strains represented hybrids between the resident P. cactorum and the apparently recently introduced P. hedraiandra. Most strains had the mitochondrially inherited cytochrome oxidase I (Cox I) gene typical of one putative parent P. hedraiandra, while one single strain had that of the other putative parent, consistent with the hybrid hypothesis. Our data also suggest that the hybrids are evolving. The hybrids have proliferated on multiple new hosts in the Netherlands.     

Effets de divers herbicides sur la croissance mycélienne de souches de Botrytis cinerea pers et de Penicillium expansum Link, sensibles ou résistantes à certains fongicides

Effects of various herbicides on mycelial growth of strains of Botrytis cinerea. Pers. and Pénicillium expansum Link, sensitive or resistant to certain fungicides Of seventy herbicides tested, thirty-eight were slightly toxic to B. cinerea (CI50, concentration giving 50% inhibition of the speed of mycelial growth, exceeding or equal to 100g of herbicide/ml of nutrient solution) and, of those, ten had no effect even at 1000 g/ml. The most active products (CI50 less than 10 g/ml) were Chlorthiamid, dichlobénil, nitrofen, propyzamide and phenolic derivatives (DNOC, ioxynil, PCP). In most cases P. expansum was less sensitive than B. cinerea except to endothal, propachlor, prynachlor and certain substituted ureas. Strains resistant to the benzimidazole fungicides (carbendazim, thiabendazole etc.) show increased sensitivity to certain carbamade herbicides (barban, chlorbufam etc.), this indicates the existence of a negative cross resistance between these groups of antimitotic pesticides. Strains resistant to the cyclic-imide fungicides (iprodionc, procymidone, vinclozolin) and to various aromatic compounds (biphenyl. chloroneb, dicloran etc.) may also be resistant to bipyridilium, dinitroanilinc and diphenylethcr herbicides, to chlorthamid. dichlobénil and oxadiazon. This cross resistance between pesticides with different biochemical modes of action has yet to be explained.     

Effects of selected pesticides and adjuvants on germination and vegetative growth of Phomopsis amaranthicola, a biocontrol agent for Amaranthus spp.

Phomopsis amaranthicola, a bioherbicide agent for Amaranthus spp., was tested in vitro for its compatibility with commercial formulations of 16 adjuvants, 24 herbicides, nine fungicides and four insecticides at 2X, 1X (highest labelled product dose rate), 0.75X, 0.5X and 0.25X concentrations. These chemicals were tested for their effects on spore germination. Selected herbicides and fungicides at 1X were also tested for their influence on colony growth and sporulation. All tested compounds were finally categorized in compatibility classes regarding germination, mycelial growth and sporulation such as low, medium and high compatibility. High compatibility in terms of germination and fungal colony growth was only observed with the herbicide bentazone. Many of the adjuvants tested were highly compatible in the germination studies. Most fungicides and insecticides had medium and low compatibility with P. amaranthicola. Effects of pesticides on spore germination did not fully correspond with their effects on colony growth. Thus, it is possible to integrate the use of P. amaranthicola with some herbicides, fungicides, insecticides and adjuvants but not others. A case‐by‐case selection of application methods, such as tank‐mix or sequential application, along with proper timing of applications of the fungus and the chemical agents will be necessary.     

Preliminary evaluation of nine fungicides for control ofPhytophthora cactorum andP. citrophthora associated with crown rot in peach trees

Excised twig assay and excised stem inoculation were used to evaluate nine fungicides (metalaxyl, fosetyl-Al, copper hydroxide, copper sulfate, copper oxychloride, captan, quintozene, propamocarb and chlorothalonil) againstPhytophthora cactorum andP. citrophthora associated with crown rot in peach trees. Segments were soaked in fungicide solutions at different concentrations and then inserted vertically intoP. cactorum orP. citrophthora cultures growing on cornmeal agar plus antibiotics, or inoculated by inserting a mycelium-bearing agar plug directly into the cambium. Following incubation, the bark was scraped off and length of necrosis was measured. Metalaxyl was the only fungicide that inhibited canker development on segments at the manufacturer-recommended concentration. Fosetyl-Al, captan, copper hydroxide and copper sulfate inhibited canker development at 3, 4, 4 and 8 gl^-1, respectively. The other fungicides did not affect canker length significantly compared with non-treated twigs, with the exception of propamocarb, which reduced the development ofP. cactorum on excised stems. The tested methods enabled rapid and effective evaluation of a large number of chemicals to prevent crown rot diseases caused byPhytophthora in the laboratory. http://www.phytoparasitica.org posting Dec. 5, 2001.     

The influence of two herbicides on the antifungal activity of some fungicides against Pythium butleri and Rhizoctonia solani causing damping-off of cowpea

The herbicides fluchloralin and alachlor applied to soil altered the effectiveness of fungicide treatments to seed and soil for controlling cowpea damping-off. These herbicides also modified the in-vitro toxicity of the fungicides to the mycelial growth of Pythium butleri and Rhizoctonia solani in a nutrient medium. Both herbicides reduced the toxicity of 2-methoxyethylmercury chloride (MEMC) and propamocarb to the growth of P. butleri, and of carbendazim to the growth of R. solani, but enhanced the toxicity of captafol and quintozene to P. butleri and R. solani, respectively. In pot tests, quintozene gave better control of R. solani damping-off in soil treated with fluchloralin or alachlor than in untreated soil, whereas disease control by carbendazim was decreased in similarly treated soils. Both herbicides attenuated the effectiveness of MEMC and captafol to control the damping-off caused by P. butleri; the efficacy of propamocarb was increased by alachlor but was decreased by fluchloralin. The implications of herbicide-fungicide interactions are discussed in the context of fungicidal control of root diseases in herbicide-treated soil.     

Biological control of sclerotinia stem rot of canola using antagonistic bacteria

Stem rot caused by Sclerotinia sclerotiorum is a major fungal disease of canola worldwide. In Australia the management of stem rot relies primarily on strategic application of synthetic fungicides. In an attempt to find alternative strategies for the management of the disease, 514 naturally occurring bacterial isolates were screened for antagonism to S. sclerotiorum. Antifungal activity against mycelial growth of the fungus was exhibited by three isolates of bacteria. The bacteria were identified as Bacillus cereus (SC‐1 and P‐1) and Bacillus subtilis (W‐67) via 16S rRNA sequencing. In vitro antagonism assays using these isolates resulted in significant inhibition of mycelial elongation and complete inhibition of sclerotial germination by both non‐volatile and volatile metabolites. The antagonistic strains caused a significant reduction in the viability of sclerotia when tested in a greenhouse pot trial with soil collected from the field. Spray treatments of bacterial strains reduced disease incidence and yielded higher control efficacy both on inoculated cotyledons and stems. Application of SC‐1 and W‐67 in the field at 10% flowering stage (growth stage 4·00) of canola demonstrated that control efficacy of SC‐1 was significantly higher in all three trials (over 2 years) when sprayed twice at 7‐day intervals. The greatest control of disease was observed with the fungicide Prosaro^® 420SC or with two applications of SC‐1. The results demonstrated that, in the light of environmental concerns and increasing cost of fungicides, B. cereus SC‐1 may have potential as a biological control agent of sclerotinia stem rot of canola in Australia.     

Survival of strawberry-pathogenic fungi Fusarium oxysporum f. sp. fragariae, Phytophthora cactorum and Verticillium dahliae under anaerobic conditions

The growth and survival of three strawberry pathogens, Fusarium oxysporum f. sp. fragariae (FOF), Phytophthora cactorum, and Verticillium dahliae, were examined in anaerobic (anoxic) conditions at several temperatures (10–40 °C). The growth and survival of these fungi were suppressed by anaerobic conditions in comparison with those in cultured aerobically. Under anaerobic conditions at 22.5 °C, tested isolates of FOF and P. cactorum grew slightly, but V. dahliae did not grow. The three fungi survive for markedly shorter time in the anaerobic conditions compared with the aerobic conditions at all tested temperatures except 40 °C for FOF and P. cactorum. Moreover, survival periods shortened as the cultivation temperature increased. These results demonstrate that anaerobic conditions contribute to eradicating these pathogens during flooding or reductive soil disinfestation.     

Influence of broad-leaved weed herbicides on the activity of fenoxaprop-P-ethyl

The activity of fenoxaprop-P-ethyl applied alone or in tank-mixture with different formulations of mecoprop or sulfonylurea herbicides was compared in a series of pot experiments using Avena fatua L. (wild oat) as a test plant. A logistic model was fitted to the results and dose–response curves of fenoxaprop-P-ethyl applied alone and in mixture with the broad-leaved weed herbicides were estimated using non-linear regressions. Tank-mixtures of fenoxaprop-P-ethyl and mecoprop or metsulfuron-methyl were antagonistic. In general, the activity of fenoxaprop-P-ethyl decreased with increasing doses of the broad-leaved herbicides. In mixture with 1200 g a.i. ha^?1 mecoprop, doses of fenoxaprop-P-ethyl had to be increased by 60% to 130% (dependent on formulation) to obtain the same effect as when fenoxaprop-P-ethyl was applied alone. Both the active and the inactive isomers of mecoprop were involved in the antagonism, and the ester formulation of mecoprop-P was less antagonistic than the amine formulation. In mixture with the recommended dose of 8 g a.i. ha^?1 of metsulfuron-methyl, doses of fenoxaprop-P-ethyl had to be increased by 20% to 110% to obtain the same effect as with fenoxaprop-P-ethyl applied alone. Fenoxaprop-P-ethyl did not lose activity when applied in mixture with recommended doses of chlorsulfuron, tribenuron and amidosulfuron. Antagonism of the sulfonylurea herbicides seemed to be related to the susceptibility of A.?fatua to these herbicides.     

Effect of chitin on biological control activity of Bacillus spp. and Trichoderma harzianum against root rot disease in pepper (Capsicum annuum) plants

Two bacterial isolates and one strain of Trichoderma harzianum were tested alone and in combination with chitin for efficacy in control of root rot disease caused by Phytophthora capsici and Rhizoctonia solani in pepper plants under greenhouse conditions. These bacteria (Bacillus subtilis HS93 and B. licheniformis LS674) were isolated from repeatedly washed roots of pepper plants. In in vitro assays, HS93, LS674 and T. harzianum were antagonistic against P. capsici and R. solani and produced high levels of chitinase. Seed treatment and root drenching with bacterial suspensions of HS93 with 0.5% chitin was more effective against Phytophthora and Rhizoctonia root rot than addition of the organisms without chitin. LS674 and T. harzianum reduced Rhizoctonia but not Phytophthora root rot. In two greenhouse tests, seed treatment and root drenching with HS93 amended with chitin enhanced its biocontrol activity against P. capsici but not on R. solani. The effects of LS674 and T. harzianum against R. solani were significantly enhanced when they were used as suspensions with 0.5% chitin for root drenching, but this had no effect on P. capsici. In both greenhouse experiments, the use of 0.5% chitin alone for root drenching reduced Rhizoctonia root rot. Reduction of root rot disease was accompanied by increased yield. These results show that the antagonistic activity of HS93, LS674 and T. harzianum may be stimulated by chitin resulting in significant improvements in their effectiveness against pathogens.     

Selection and Screening of Endorhizosphere Bacteria from Solarized Soils as Biocontrol Agents Against Verticillium dahliae of Solanaceous Hosts

Verticillium dahliae antagonistic endorhizosphere bacteria were selected from root tips of tomato plants grown in solarized soils. Fifty-three out of the 435 selected bacterial isolates were found to be antagonistic against V. dahliae and several other soilborne pathogens in dual cultures. Significant biocontrol activity against V. dahliae in glasshouse trials was demonstrated in three of 18 evaluated antagonistic isolates, provisionally identified as Bacillus sp. Although fluorescent pseudomonads were also isolated from root tips of tomato plants, none of the tested isolates exercised any significant antagonistic activity against V. dahliae in dual cultures. So these isolates were not tested in glasshouse trials in this study. Finally, two of the most effective bacterial isolates, designated as K-165 and 5-127, were shown to be rhizosphere colonizers, very efficient in inhibiting mycelial growth of V. dahliae in dual cultures and successfully controlling Verticillium wilt of solanaceous hosts. In glasshouse experiments, root dipping or soil drenching of eggplants with bacterial suspension of 10⁷cfu ml^–1 resulted in reduced disease severity expressed as percentage of diseased leaves (40–70%) compared to the untreated controls under high V. dahliae inoculum level (40 microsclerotia g^–1 soil). In heavily Verticillium infested potato fields, experiments with potato seeds dusted with a bacterial talc formulation (10⁸cfu g^–1 formulation), showed a significant reduction in symptom development expressed as percentage of diseased potato plants and a 25% increase in yield over the untreated controls. As for their effectiveness in increasing plant height, both bacterial isolates K-165 and 5-127 produced indolebutyric, indolepyruvic and indole propionic acids. Both antagonists are considered as plant growth promoting rhizobacteria bacteria since significantly increased the height of treated plants compared with the untreated controls. Chitinolytic activity test showed that both isolates were able to produce chitinase. Testing rhizospheric and endophytic activity of the antagonists it was shown that although the bacteria are rhizosphere inhabitants they also preferentially colonize the endorhizosphere of tomatoes and eggplants. Fatty acid analysis showed that isolate K-165 could belong to Paenibacillus alvei while 5-127 to Bacillus amiloliquefaciens.     

Interaction between benzoylprop ethyl, flamprop methyl or flamprop isopropyl and herbicides used for broadleaved weed control

A marked antagonism of A. fatua control was found when 2,4-D, dicamba, 2,4-D-dicamba-mecoprop or bromoxynil were added to benzoylprop ethyl, flamprop methyl or flamprop isopropyl. Because of the much poorer control of A. fatua by these mixtures obtaining broad spectrum weed control with them in one spray operation would not be possible. The A. fatua herbicides did not affect the activity of the added herbicides on Fagopyrum lataricum. In eight out of nine mixtures tested there was no significant antagonism in the field conditions when MCPA or bromoxynil-MCPA was added to the A. fatua herbicides. There were significant antagonistic effects, however, in six out of nine such mixtures in glasshouse experiments. This suggests that under farm use conditions benzoylprop ethyl, flamprop methyl or fiamprop isopropyl can be mixed with MCPA amine or ester or with bromoxynil-MCPA to obtain broad spectrum weed control from one spray operation, though slightly poorer A. fatua control may be expected with these mixtures.     

Effects of some commercial herbicides on rhizobia and their symbiosis with peanuts

Four herbicides commonly used in Israel for controlling weeds in peanuts were evaluated under field and screenhouse conditions. Terbutryn (Terbutrex 50, w.p.), ethalfluralin (Sonalan 333, e.c.), dinitramine (Cobex 240, e.c.) and alachlor (Alapaz 480, e.c.), used at recommended levels, had no adverse effect on nodulation rate, nitrogenase activity, total nitrogen of peanut tops or pod yield, compared with control (inoculated but herbicide non-treated) plants. Studies were conducted to determine the relative toxicity in vitro of the herbicides on each of four Rhizobium strains used for commercial peat inoculant production. The results showed that at up to 94 μg g^?1 the herbicides has no inhibitory effect on the growth of rhizobia. The sensitivity of Rhizobium strains to different rates of the chemicals decreased in the order: dinitramine>alachlor>ethalfluralin>terbutryn. It was found that various strains differ in their sensitivity to the herbicides tested.     

An effective biocontrol bioformulation against Phytophthora blight of pepper using growth mixtures of combined chitinolytic bacteria under different field conditions

Phytophthora blight of pepper caused by Phytophthora capsici has devastating consequences when combined with other pathogens, including Rhizoctonia solani, Fusarium oxysporum, and Fusarium solani. In order to develop a field-effective biocontrol strategy against Phytophthora blight of pepper, three chitinolytic bacteria, Serratia plymuthica strain C-1, strongly antagonistic to P. capsici, Chromobacterium sp. strain C-61, strongly antagonistic to R. solani, and Lysobacter enzymogenes strain C-3, antagonistic to R. solani and Fusarium spp., were selected. In pot studies, application of cultures combining the three bacterial strains effectively suppressed Phytophthora blight more than application of any single bacterial strain. Bioformulations developed from growth of the strains in a simple medium containing chitin under large batch conditions resulted in effective control in field applications. Efficacy of the bioformulated product depended on both the dose and timing of application. Although the undiluted product suppressed Phytophthora blight under all field conditions, a 10-fold diluted product was effective in solar-sterilized greenhouses and in fields with crop rotation. These results suggest that the developed product could be a new effective system to control Phytophthora blight disease in pepper.