Role of cyanide production by Pseudomonas fluorescens CHA0 in the suppression of root-knot nematode, Meloidogyne javanica in tomato

Summary Pseudomonas fluorescens strain CHA0 produces hydrogen cyanide (HCN), a secondary metabolite that accounts largely for the biocontrol ability of this strain. In this study, we examined the role of HCN production by CHA0 as an antagonistic factor that contributes to biocontrol of Meloidogyne javanica, the root-knot nematode, in situ. Culture filtrate of CHA0, resulting from 1/10-strength nutrient broth yeast extract medium amended with glycine, inhibited egg hatch and caused mortality of M. javanica juveniles in vitro. The bacterium cultured under high oxygen-tension conditions exhibited better inhibitory effects towards nematodes, compared to its cultivation under excess oxygen situation. Growth medium amended with 0.50 or 1.0 mM FeEDDHA further improved hatch inhibition and nematicidal activity of the strain CHA0. Strain CHA77, an HCN-negative mutant, failed to exert such toxic effects, and in this strain, antinematode activity was not influenced by culture conditions. Exogenous cyanide also inhibited egg hatch and caused mortality of M. javanica juveniles in vitro. Strains CHA0 or CHA77 applied in unsterilized sandy-loam soil as drench, caused marked suppression of root-knot disease development incited by M. javanica in tomato seedlings. However, efficacy of CHA77 was noticeably lower compared to its wild type counterpart CHA0. An increased bioavailability of iron following EDTA application in soil substantially improved nematode biocontrol potential of CHA0 but not that of CHA77. Soil infestation with M. javanica eggs resulted in significantly lower nematode population densities and root-knot disease compared to the juveniles used as root-knot disease-inducing agents. Strain CHA0 significantly suppressed nematode populations and inhibited galling in tomato roots grown in soil inoculated with eggs or juveniles and treated with or without EDTA. Strain CHA0 exhibited greater biocontrol potential in soil inoculated with eggs and treated with EDTA. To demonstrate that HCN synthesis by the strain CHA0 acts as the inducing agent of systemic resistance in tomato, efficacy of the strain CHA0 was compared with CHA77 in a split root trial. The split-root experiment, guaranteeing a spatial separation of the inducing agent and the challenging pathogen, showed that HCN production by CHA0 is not crucial in the induction of systemic resistance in tomato against M. javanica, because the HCN-negative-mutant CHA77 induced the same level of resistance as the wild type but exogenous cyanide in the form of KCN failed to trigger the resistance reaction. In the root section where both nematode and the bacterium were present, strain CHA0 reduced nematode penetration to a greater extent than CHA77, suggesting that for effective control of M. javanica, a direct contact between HCN-producing CHA0 and the nematode is essential.     

Non-pathogenic Fusarium solani represses the biosynthesis of nematicidal compounds in vitro and reduces the biocontrol of Meloidogyne javanica by Pseudomonas fluorescens in tomato

AIMS: The aim of the present investigation was to determine the influence of various Fusarium solani strains on the production of nematicidal agent(s) in vitro and biocontrol of Meloidogyne javanica in tomato by Pseudomonas fluorescens strains CHA0 and CHA0/pME3424. METHODS AND RESULTS: Culture filtrates (CF) of P. fluorescens strain CHA0 and its diacetylphloroglucinol-overproducing derivative CHA0/pME3424 caused substantial mortality of M. javanica juveniles in vitro. Bacterial growth medium amended with the growth medium of F. solani repressed the nematicidal activity of the bacteria. Methanol extract of F. solani CF resulting from Czapek's Dox liquid (CDL) medium without zinc amendment repressed the nematicidal activity of the bacteria while the CF obtained from CDL medium amended with zinc did not. Conidial suspension of F. solani strain Fs5 (repressor strain for the biosynthesis of nematicidal compounds in P. fluorescens) reduced biocontrol potential of the bacterial inoculants against M. javanica in tomato while strain Fs3 (non-repressor) did not. CONCLUSIONS: Fusarium solani strains with increased nematicidal activity repress the biosynthesis of nematicidal compounds by P. fluorescens strains in vitro and greatly alter its biocontrol efficacy against root-knot nematode under natural conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: Fusarium solani strains are distributed worldwide and found in almost all the agricultural fields which suggest that some mycotoxin-producing strains will also be found in almost any soil sample taken. Besides the suppressive effect of these metabolite-producing strains on the production of nematicidal compound(s) critical in biocontrol, F. solani strains may also affect the performance of mycotoxin-sensitive biocontrol bacteria effective against plant-parasitic nematodes.     

Trichoderma harzianum enhances the production of nematicidal compounds in vitro and improves biocontrol of Meloidogyne javanica by Pseudomonas fluorescens in tomato

AIMS: To determine the influence of soil-borne fungus Trichoderma harzianum on the biocontrol performance of Pseudomonas fluorescens strain CHA0 and its 2,4-diacetylphloroglucinol (DAPG) overproducing derivative CHA0/pME3424 against Meloidogyne javanica. METHODS AND RESULTS: Amendment of the culture filtrate (CF) or methanol extract of the CF of a T. harzianum strain Th6 to P. fluorescens growth medium enhanced the production of nematicidal compound(s) by bacterial inoculants in vitro. In addition, bacteria overwhelmingly expressed phl'-'lacZ reporter gene when the medium was amended with CF of T. harzianum. Pseudomonas fluorescens and T. harzianum applied together in unsterilized sandy loam soil caused greater reduction in nematode population densities in tomato roots. CONCLUSIONS: Trichoderma harzianum improves root-knot nematode biocontrol by the antagonistic rhizobacterium P. fluorescens both in vitro and under glasshouse conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The synergistic effect of T. harzianum on the production of nematicidal compound(s) critical in biocontrol may improve the efficacy of biocontrol bacteria against plant-parasitic nematodes. Considering the inconsistent performance of the biocontrol agents under field conditions, application of a mixture of compatible T. harzianum and P. fluorescens would more closely mimic the natural situation and might broaden the spectrum of biocontrol activity with enhanced efficacy and reliability of control.     

A novel approach to biological control with entomopathogenic nematodes: Prophylactic control of the peachtree borer, Synanthedon exitiosa

Generally, microbial control agents such as entomopathogenic nematodes are applied in a curative manner for achieving pest suppression; prophylactic applications are rare. In this study, we determined the ability of two Steinernema carpocapsae strains (All and Hybrid) to prophylactically protect peach trees from damage caused by the peachtree borer, Synanthedon exitiosa, which is a major pest of stone fruit trees in North America. In prior studies, the entomopathogenic nematodes S. carpocapsae and Heterorhabditis bacteriophora caused field suppression when applied in a curative manner to established S. exitiosa populations. In our current study, nematodes were applied three times (at 150,000–300,000 infective juveniles/tree) during September and October of 2005, 2006, and 2007. A control (water only) and a single application of chlorpyrifos (at the labeled rate) were also made each year. The presence of S. exitiosa damage was assessed each year in the spring following the treatment applications. Following applications in 2006, we did not detect any differences among treatments or the control (possibly due to a low and variable S. exitiosa infestation of that orchard). Following applications in 2005 and 2007, however, the nematode and chemical treatments caused significant damage suppression. The percentage of trees with S. exitiosa damage in treated plots ranged from 0% damage in 2005 to 16% in plots treated with S. carpocapsae (Hybrid) in 2007. In control plots damage ranged from 25% (2005) to 41% (2007). Our results indicate that nematodes applied in a preventative manner during S. exitios’s oviposition period can reduce insect damage to levels similar to what is achieved with recommended chemical insecticide treatments.     

Maleylacetate reductase of Pseudomonas sp. strain B13: dechlorination of chloromaleylacetates,metabolites in the degradation of chloroaromatic compounds

The maleylacetate reductase of 3-chlorobenzoate-grown cells of Pseudomonas sp. strain B13 has been purified 50-fold. The enzyme converted 2-chloromaleylacetate to 3-oxoadipate with temporary occurrence of maleylacetate; 1 mol of chloride was eliminated during the conversion of 1 mol of 2-chloro- and 2,3-dichloromaleylacetate; 2 mol of NADH were consumed per mol of 2-chloro- and 2,3-dichloromaleylacetate while only 1 mol was necessary to catalyze the conversion of maleylacetate or 2-methylmaleylacetate. The maleylacetate reductase failed to use fumarylacetate as a substrate. The role of the enzyme in the chloroaromatics degradation is discussed.     

Gluconic acid: an antifungal agent produced by Pseudomonas species in biological control of take-all

Pseudomonas strain AN5 (Ps. str. AN5), a non-fluorescent Australian bacterial isolate, is an effective biological control (biocontrol) agent of the take-all disease of wheat caused by the fungus Gaeumannomyces graminis var. tritici (Ggt). Ps. str. AN5 controls Ggt by producing an antifungal compound which was purified by thin layer and column chromatography, and identified by NMR and mass spectroscopic analysis to be d-gluconic acid. Commercially bought pure gluconic acid strongly inhibited Ggt. Two different transposon mutants of Ps. str. AN5 which had lost take-all biocontrol did not produce d-gluconic acid. Gluconic acid production was restored, along with take-all biocontrol, when one of these transposon mutants was complemented with the corresponding open reading frame from wild-type genomic DNA. Gluconic acid was detected in the rhizosphere of wheat roots treated with the wild-type Ps. str. AN5, but not in untreated wheat or wheat treated with a transposon mutant strain which had lost biocontrol. The antifungal compounds phenazine-1-carboxylic acid and 2,4-diacetylphloroglucinol, produced by other Pseudomonads and previously shown to be effective in suppressing the take-all disease, were not detected in Ps. str. AN5 extracts. These results suggest that d-gluconic acid is the most significant antifungal agent produced by Ps. str. AN5 in biocontrol of take-all on wheat roots.     

Improving the biological control of Botryodiplodia disease on some Annona cultivars using single or multi-bioagents in Egypt

Botryodiplodia disease caused by Botryodiplodia theobromae is a recently disease of some Annona cultivars in Egypt, particularly in Behera Governorate, characterized by stem purple lesions, dieback, flowers, and fruits dry and soft rot. Six fungal and bacterial bioagents, i.e., Trichoderma koningii, Trichoderma hamatum, Pseudomonas fluorescens, Pseudomonas putida, Tilletiopsis minor, and Tilletiopsis washingtonensis were tested either solely or at different amalgamations against Botryodiplodia disease, as foliar spraying using three Annona cultivars, i.e., Balady and Abd El-Razik (Annona squamosa) and Hindy (Annona cherimola). In vitro, studies revealed a significant inhibition towards the conidial germination of B. theobromae as well as on the disease incidence on artificially inoculated branches and fruits in the presence of the aforementioned bioagents. An unmistakable reduction in the disease was conspicuous under the action of multi-bioagent conduct. The bioagents were tested during 2003 and 2004 agricultural seasons under the field conditions at Nobaria, (Behera Governorate). A single application and all possible mixture of two or three of the bioagents were applied at 15 days intervals as a foliar spray. Botryodiplodia disease severity and sporulation of the pathogen were always reduced, when the multi-bioagents were applied. When Trichoderma spp. and Pseudomonads spp. were blended together, the disease was greatly abridged in the three tested cultivars compared to any of the sole bioagents. The multi-bioagents were more effective than any sole or even double treatments. The application of multi-bioagents also resulted in a significant increase of fruit yield.     

Introduction and establishment of parasitoids for the biological control of the apple ermine moth, Yponomeuta malinellus (Lepidoptera: Yponomeutidae), in the Pacific Northwest

Four parasitoids were imported from five countries in Eurasia and released in northwestern Washington, US, to control the apple ermine moth (AEM), Yponomeuta malinellus Zeller, which colonized the Northwest around 1981. From 1988 to 1991, 95,474 individuals of Ageniaspis fuscicollis (Dalman) from France, China, Korea, and Russia were released in Washington. Parasitism of AEM increased 4- to 5-fold over that produced by preexisting natural enemies between 1989 and 1994 at 22 monitored sites. Subsequently, the wasp dispersed up to 20 km from release sites. A. fuscicollis also parasitized the cherry ermine moth, Yponomeuta padellus (L.), which was discovered in the Pacific Northwest in 1993. A total of 1813 individuals of Herpestomus brunnicornis (Gravenhorst) from France, Korea, and Japan were released in 1989–1991, and 26 wasps were recovered in 1994–1995. From 1989 to 1991, 2647 Diadegma armillata (Gravenhorst) individuals from France were released. D. armillata was recovered at one site in 1991 two months following release, but no other recoveries have been made. A total of 8274 Eurystheae scutellaris(Robineau-Desvoidy) individuals were released in 1989 to 1991. However, this tachinid has not been recovered. A consistent decline of AEM populations occurred in 1989–1995, including at sites where A. fuscicollis was not recovered, suggesting other factors also contributed to this pest’s decline. Now well established in western Washington, A. fuscicollis may help suppress future outbreaks of Y. malinellus and its congener, Y. padellus.     

Establishment of papaya banker plant system for parasitoid, Encarsia sophia (Hymenoptera: Aphilidae) against Bemisia tabaci (Hemiptera: Aleyrodidae) in greenhouse tomato production

The silverleaf whitefly, Bemisia tabaci biotype B (Gennadius) (Hemiptera: Aleyrodidae), is a key pest of tomato (Solanum lycopersicum L.) and other vegetable crops worldwide. To combat this pest, a non-crop banker plant system was evaluated that employs a parasitoid, Encarsia sophia (Girault & Dodd) (Hymenoptera: Aphelinidae) with whitefly, Trialeurodes variabilis (Quaintance) (Hemiptera: Aleyrodidae), as an alternative host for rearing and dispersal of the parasitoid to the target pest. (a) Multi-choice and no-choice greenhouse experiments were conducted to determine host specificity of T. variabilis to papaya (Carica papaya L.) and three vegetable crops including tomato, green bean (Phaseolus vulgaris L.), and cabbage (Brassica oleracea L.). The result showed that papaya was an excellent non-crop banker plant for supporting the non-pest alternative host, T. variabilis, whose adults had a strong specificity to papaya plants for feeding and oviposition in both multi-choice and no-choice tests. (b) The dispersal ability of E. sophia was investigated from papaya banker plants to tomato and green bean plants infested with B. tabaci, as well as to papaya control plants infested with T. variabilis; and (c) the percent parasitism by E. sophia on T. variabilis reared on papaya plants and on B. tabaci infested on tomato plants was also evaluated. These data proved that E. sophia was able to disperse at least 14.5 m away from papaya plants to target tomato, bean or papaya control plants within 48–96 h. Furthermore, E. sophia was a strong parasitoid of both T. variabilis and B. tabaci. There was no significant difference in percent parasitism by E. sophia on T. variabilis (36.2–47.4%) infested on papaya plants or B. tabaci (29–45.9%) on tomato plants. Thus, a novel banker plant system for the potential management of B. tabaci was established using papaya as a non-crop banker plant to support a non-pest alternative host, T. variabilis for maintaining the parasitoid to control B. tabaci. The established banker plant system should provide growers with a new option for long-term control of B. tabaci in greenhouse vegetable production. Ongoing studies on the papaya banker plant system are being performed in commercial greenhouses.     

Studies on the rust,Maravalia cryptostegiae,a potential biological control agent of rubber-vine weed,Cryptostegia grandiflora (Asclepiadaceae: Periplocoideae), in Australia,III: Host range

Seventy-one plant species, which were selected using a centrifugal phylogenetic method, were screened againstMaravalia cryptostegiae, an endemic rust of rubber-vine (Cryptostegia grandiflora) in Madagascar. All species and variants of the genusCryptostegia proved to be highly susceptible to the rust under optimum greenhouse conditions. Two other species belonging to the same subfamily Periplocoideae,Gonocrypta grevei from Madagascar andCryptolepis grayi from Australia, developed fertile sori but could still be classified as partially resistant, based on the results of a leaf clearing and staining technique. Fifteen assessment categories and 10 susceptibility ratings were designated by analysing both macro- and microsymptoms. Five resistance mechanisms were identified in the non-hosts and these are described and illustrated. Resistance reactions ranged from complete suppression of spore germination on the plant cuticle to restriction of sorus development due to the collapse of rust haustoria. The significance of host range studies are discussed in relation to the use of rust fungi as classical biological control agents of weeds, and specifically the release ofM. cryptostegiae in Australia.     

Successful biological control of mist flower (Ageratina riparia) in New Zealand: Agent establishment, impact and benefits to the native flora

The white smut fungus (Entyloma ageratinae) and the gall fly (Procecidochares alani) were released in New Zealand in 1998 and 2001 respectively to suppress mist flower (Ageratina riparia). The fungus established and spread rapidly, crossing 80 km of sea to Great Barrier Island within 2 years. The mean number of P. alani galls increased exponentially to 1.96/stem at release sites, but dispersal was slow. The impact of the biocontrol agents was monitored once annually from 1998/99 to 2003/04, at up to 51 sites in the North Island. The mean percentage of live leaves infected with fungus rapidly reached nearly 60%. Maximum plant height declined significantly. In heavy infestations, mean percentage cover of mist flower declined from 81 to 1.5%. Galls were only recorded towards the end of the impact study, and at low mean numbers. As mist flower declined, the species richness and mean percentage cover of native plants increased. In contrast, the species richness and mean percentage cover of exotic plants (excluding mist flower) did not change significantly. Many plant species colonizing the plots were important native mid- or late-successional shrubs or trees. With few exceptions, the exotic plant species common in the plots were not weeds that appeared to threaten native forest habitats. There was only a weak “replacement weed effect” from the potentially serious invader African club moss (Selaginella kraussiana). These data, together with reports of reduced threats to rare endemic plants from mist flower, suggest this rapid, well-monitored weed biocontrol program was very successful.     

Studies on the rustMaravalia cryptostegiae,a potential biological control agent of rubber-vine weed (Cryptostegia grandiflora,Asclepiadaceae: Periplocoideae) in Australia,I: Life-cycle

Three spore types are described forMaravalia cryptostegiae: hemileioid urediniospores; thin-walled, hyaline, ellipsoidal, non-resting teliospores and ovoid to lacrimoid basidiospores. Field surveys in the Madagascan native range of rubber-vine failed to confirm the existence of spermogonia and morphologically distinct aecia within the life-cycle. Greenhouse inoculations with basidiospores were unsuccessful. Cytological studies revealed that rubber-vine rust has a similar nuclear cycle to that reported for coffee leaf rust,Hemileia vastatrix. The working hypothesis is proposed thatMaravalia cryptostegiae is a primitive, autoecious tropical forest rust with only a short or partially expanded life-cycle represented by two teliospore forms. The predominant, functional form is uredinioid with a novel nuclear cycle, in which there is a delayed meiotic division (the Kamat phenomenon). The non-dispersed form appears to be vestigial or non-functional since it germinates to produce a metabasidium with genetically variable and unstable basidiospores. The relationships and evolutionary significance of the generaMaravalia andHemileia are discussed.     

Nitrogen control in Pseudomonas aeruginosa: A role for glutamine in the regulation of the synthesis of NADP-dependent glutamate dehydrogenase,urease and histidase

In Pseudomonas aeruginosa the formation of urease, histidase and some other enzymes involved in nitrogen assimilation is repressed by ammonia in the growth medium. The key metabolite in this process appears to be glutamine or a product derived from it, since ammonia and glutamate did not repress urease and histidase synthesis in a mutant lacking glutamine synthetase activity when growth was limited for glutamine. The synthesis of these enzymes was repressed in cells growing in the presence of excess glutamine. High levels of glutamine were also required for the derepression of NADP-dependent glutamate dehydrogenase formation in the glutamine synthetase-negative mutant.     

Potential exposure of a classical biological control agent of the soybean aphid, Aphis glycines, on non-target aphids in North America

In summer 2007, the Asian parasitoid Binodoxys communis (Hymenoptera: Braconidae) was released in North America for control of the exotic soybean aphid, Aphis glycines (Hemiptera: Aphididae). Despite its comparatively narrow host range, releases of B. communis may still constitute a risk to native aphid species. To estimate the risk of exposure of non-target aphids to B. communis, we merged assessments of temporal co-occurrence with projections of spatial overlap between B. communis and three native aphid species, and in-field measurements of the incidence of ecological filters that may protect these aphids from parasitism. Temporal co-occurrence was assessed between A. glycines and native aphids (Aphis asclepiadis, Aphis oestlundi, and Aphis monardae) at four different locations in Minnesota, USA. The degree of temporal overlap depended greatly on location and aphid species, ranging between 0 and 100%. All of the native aphids were tended by multiple species of ants, with overall ant-attendance ranging from 26.1 to 89.6%. During temporal overlap with A. glycines, 53 ± 11% of A. monardae colonies were partly found in flower heads of their host plant, with flowers acting as a physical refuge for this aphid. The extent of geographic overlap between B. communis and native aphids based upon Climex modeling was 17–28% for A. monardae, 13–22% for A. oestlundi, 46–55% for A. asclepiadis and 12–24% for the A. asclepiadis species complex. The estimated overall probability of potential exposure of B. communis on native aphids was relatively low (P = 0.115) for A. oestlundi and high (P = 0.550) for A. asclepiades. Physical and ant-mediated refuges considerably lowered probability of population-level impact on A. monardae, and could lead to substantial reduction of exposure for the other native aphids. These findings are used to make broader statements regarding the ecological safety of current B. communis releases and their potential impact on native aphid species in North America.     

Performance and impact of the biological control agent Xubida infusella (Lepidoptera; Pyralidae) on the target weed Eichhornia crassipes (waterhyacinth) and on a non-target plant, Pontederia cordata (pickerelweed) in two nutrient regimes

Xubida infusella (Walker) (Lepidoptera: Pyralidae) is potentially a useful biological control agent targeting Eichhornia crassipes (waterhyacinth) in the USA but many regions infested with waterhyacinth are also inhabited by an alternative native host, Pontederia cordata (pickerelweed). Experiments were conducted in Australia to assess the impact of X. infusella on pickerelweed compared to waterhyacinth where both these plants were available and X. infusella had already been released. Overall X. infusella had a greater impact on pickerelweed than on waterhyacinth. More than one larva per plant was required to reduce the total shoot dry weight of waterhyacinth but only one larva per plant reduced the total shoot dry weight of pickerelweed. Insect feeding caused the number of secondary shoots (daughter plants) of pickerelweed to double whereas the number of daughter plants produced by waterhyacinth remained unchanged. We suggest this indicates a considerable impact on pickerelweed rather than effective compensation for insect damage because the shoots produced were very small. Waterhyacinth produced a constant number of daughter plants when fed on by up to three larvae per plant. Higher nitrogen status of both species of host plant increased the rate of larval development and pupal weight of X. infusella. The weight and fecundity of X. infusella reared on pickerelweed were lower than those reared on waterhyacinth but large numbers of progeny were produced on both plant species. This experiment demonstrates a considerable impact of X. infusella on pickerelweed suggesting this plant is at risk from this agent if released in the USA where pickerelweed is present. The considerable impact on waterhyacinth demonstrates the potential for this insect to contribute to waterhyacinth control in countries where risk assessment favours release.     

Post-release survey to assess impact and potential host range expansion by Amitus hesperidum and Encarsia perplexa, two parasitoids introduced for the biological control of the citrus blackfly, Aleurocanthus woglumi in Dominica

Four years after the release of two exotic parasitoids, Amitus hesperidum Silvestri (Hymenoptera: Platygasteridae) and Encarsia perplexa Huang and Polaszek (Hymenoptera: Aphelinidae) for the classical biological control of the citrus blackfly (CBF), Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae) in Dominica, a survey was conducted to assess establishment as well as potential nontarget effects especially on Aleyrodidae and other related taxa. CBF populations were low to non-existent in 50 of 51 field sites examined. At the site where CBF was encountered, both E. perplexa and A. hesperidum were present and CBF populations were declining. The two parasitoids were not among the several species collected on nontarget Aleryodidae and Hemiptera. It is concluded that E. perplexa and A. hesperidum have kept CBF populations under effective biological control in Dominica and there is no evidence of any nontarget effects on other Aleyrodidae or their natural enemies. Handling Editor: Dirk Babendreier.     

Rearing,release and settlement prospect in Italy of <Emphasis Type="Italic">Torymus sinensis</Emphasis>, the biological control agent of the chestnut gall wasp <Emphasis Type="Italic">Dryocosmus kuriphilus</Emphasis>

Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), is one of the most serious pests attacking chestnut trees. Recently it was incidentally introduced into Northwest Italy and it is now spreading throughout Europe. This pest was successfully controlled in Japan by introducing a parasitoid, Torymus sinensis Kamijo (Hymenoptera: Torymidae), from China’s mainland. Following this successful experience, the parasitoid was introduced into Italy from Japan. One year of preliminary studies led to a successful method of rearing imported galls with a synchronization between the parasitoid’s emergence and the presence of the target galls in the field. In two consecutive years, a total of 2,117 individuals were released in several sites covering most of the infested area. There are encouraging data about the settlement of the parasitoid and its synchrony with the host’s cycle: from about 64,000 host galls collected in the field over 200 T. sinensis were reared. The role of native parasitoids associated with the chestnut gall pest in its Italian distribution range is also discussed.