Spur Blight Research Articles

CONTROL OF THE DEVELOPMENT OF SUMMER RASPBERRY DISEASES USING MONO-AND TWO COMPONENT FUNGICIDES FROM THE TRIAZOLE GROUP UNDER THE CONDITIONS OF BELARUS

Two year researches on the efficiency of monocomponent fungicide Topaz, CE and two component fungicide Luna experience, SC from the triazole group were conducted when controlling the development of summer raspberry diseases. As a result, it was established that the efficiency of both preparations against anthracnose and spur blight was 56,4–70,2 % and 66,2–72,6 % respectively when used in minimal doses, and 75,7–83,5 % and 80,6–84,4 % when used in maximum doses. The efficiency against gray rot over the years of the research fluctuated from 67,8 % to 89,9 %.

Biological control of important fungal diseases of potato and raspberry by two Bacillus velezensis strains.

Stem canker and black scurf caused by Rhizoctonia solani are the important diseases in potato, while spur blight caused by Didymella applanata is a major disease in red raspberry. In Western Siberia, both crops are grown predominantly in small-scale farming that requires maximal usage of biological products for plant protection instead of chemicals. We evaluated two promising Bacillus velezensis strains BZR 336 g and BZR 517 isolated in the south of Russia (45°1′N, 38°59′E) for their biological control potentials against the potato and red raspberry diseases under the more severe weather conditions of Western Siberia (55°1′N, 82°55′ E). We tested two techniques to apply biocontrol agents: (1) coating the seeds (potato tubers) and (2) spraying over the plants (raspberry canes). In each case, we estimated B. velezensis strains on two plant cultivars differed by the disease resistance. The degree of B. velezensis influence on disease incidence and severity depended on the bacterial strain, the protected plant, and its cultivar. We also demonstrated that two B. velezensis strains significantly stimulated plant growth of potato, which contributed to the plant productivity on both cultivars. The BZR 336 g strain affected the potato productivity more than the BZR 517 strain. Under the influence of both bacterial strains, raspberry yield was significantly higher compared to the control on the susceptible cultivar. These findings indicated that two southern B. velezensis strains had proved their efficacy as biological control agents in the control of the serious fungal infection of potato and raspberry plants under the more severe ecological conditions of Western Siberia. For the first time, we demonstrated B. velezensis strains potential for use as biological control agents against R. solani on potato, and against D. applanata on red raspberry.

Sensitivity and efficacy of the succinate dehydrogenase inhibitor fluxapyroxad, against raspberry spur blight fungus Didymella applanata

Didymella applanata, the causal agent of raspberry spur blight, is a destructive plant pathogen that can cause serious reductions in total yield. The use of fungicides plays a crucial role in successful control of the pathogen. The sensitivity of 94 isolates (66 collected during 2013 and 28 in 2017) of D. applanata to the succinate dehydrogenase inhibitor, fluxapyroxad, was evaluated in this study. In addition, the efficacy of fluxapyroxad in raspberry spur blight control in the field was determined. The isolates tested in this study showed different sensitivity to fluxapyroxad in vitro. The EC50 values of total number of isolates tested were ranged from 0.82 to 5.92 µg ml−1. The ranges of EC50 values for the isolates varied between the localities where the isolates originated from and also the year of isolation. The mean EC50 values in the group of isolates obtained in 2013 were 1.95 µg ml−1 ± 0.81 (0.82 to 4.05 µg ml−1), while the EC50 values for those isolated in 2017 were ranged from 1.16 to 5.78 µg ml−1 (mean = 3.24 µg ml−1 ± 1.38). The efficacy trials were conducted during 2017 and 2018 in a commercial raspberry field at two locations in western part of Serbia. Applied in both concentration rates 0.02 and 0.03% of the formulated product (0.006 and 0.009% of a.i.), fluxapyroxad showed a very high efficacy in spur blight control in practical condition.

Sweet cherry collection composition and breeding value of Melitopol experimental station of horticulture

Aim. To evaluate the composition and breeding potential of a gene poolcollection of sweet cherry varieties of M.F. SydorenkoMelitopolResearch Station of Fruit Growing of the Institute of Horticulture, NAAS of Ukraine. Result and Discussion.The results of studying the morphological, economic and biological features of sweet cherry (Cerasusavium L. Moench) varieties from the gene pool collection of MelitopolExperimental Station of Horticulturenamed after M.F. Sidorenko of the Institute of Horticulture of NAAS are presented. The history of the collection creation and the genealogy of modern Ukrainian varieties were analyzed. We found that they were the 1st and 2nd generations of traditional Western European varieties. Major sweet cherry varieties that had been most often used in developing modern Ukrainian assortment, were identified. Analysis of the collection showed that 111 accessions of 129 were varieties bred in Melitopol, 40 of which are officially registered.The other accessions are elite forms, which failed the state variety trials or are being tested according to the competitive design. Among the latter, promising forms (candidates for varieties and pre-breeding forms) were distinguished, as they are sources of valuable economic traits. It was determined that the morphogenic process had contributed to the diversity in fruit quality features, which enabled building up a trait collection of sweet cherries for 20 traits with 82 levels of their expression. However, morphogenesis almost did not affect the growth power, fructification nature, generative organs, fructification time and resistance to diseases, therefore there are no significant differences in these features between the collection accessions bred at Melitopol Experimental Station of Horticulture named after M.F. Sidorenko of the Institute of Horticulture of NAAS. Most of the varieties grown on Magalebian cherry plantlet have extensive crowns, bear fruit on "May bouquets" and, after one-year growth, are winter hardy, tolerant to drought, moderately and highly resistant to spur blight and leaf spot as well as self-infertile. On this parent stock, most of the varieties come into fruition after 5-6 years and quickly increase their yields. It was established that enrichment of the gene pool collection with valuable introduced accessions and their wide involvement in hybridization were currently the key objectives aimed at expansion of morphogenesis limits to obtain competitive varieties with high adaptability, productivity and marketability. Conclusions. Modern Ukrainian varieties are the 1st and 2nd generations of traditional Western European varieties. German variety Drogansgelbeknorpelkirsche (DroganaZhyoltaya) with its clone Napoleon Belaya and Russian-Ukrainian variety Valeriy Chkalov were the most actively used in their development. 86% of the gene pool collection of MelitopolExperimental Stationof Horticulture named after M.F. Sidorenkoof the Institute of Horticulture of NAAS are varieties bred in Melitopol differing mainly in ripening time and fruit quality. The collection contains released varieties, a number of sources of valuable traits and, as a tool for the effective implementation of modern breeding programs, requires enrichment with varieties of other eco-geographical groups.

Neoscytalidium dimidiatum Causing Canker, Shoot Blight and Fruit Rot of Almond in California.

Almond trees with trunk and branch cankers were observed in several orchards across almond-producing counties in California. Symptoms of cankers included bark lesions, discoloration of xylem tissues, longitudinal wood necrosis, and extensive gumming. Spur and shoot blight associated with rotted fruit were detected in two orchards in Kern County. The fungus Neoscytalidium dimidiatum was consistently recovered from the various cankers, infected fruit, and blighted shoots and its identity was confirmed based on phylogenetic and morphological studies. Phylogenetic analyses of the internal transcribed spacer, translation elongation factor 1-α, and β-tubulin genes comparing 47 strains from California with reference specimens within the family Botryosphaeriaceae and coupled with detailed morphological observations validated the identity of the pathogenic fungus. Pathogenicity tests conducted in the field using 1- to 2-year-old branches inoculated with mycelium plugs or conidial suspensions and attached fruit inoculated with conidial suspensions fulfilled Koch's postulates. N. dimidiatum appeared highly virulent in almond-producing cankers of up to 22 cm in length within 4 weeks using mycelium plug inoculations as well as severe fruit rot combined with spur blight on the fruit-bearing spurs. This study reports, for the first time, the fungus N. dimidiatum as a pathogen of almond in California causing canker, shoot blight, and fruit rot. Disease symptoms are described and illustrated.

Efficacy of fungicides with different modes of action in raspberry spur blight (Didymella applanata) control

Efficacy trials of four multi-site fungicides (copper hydroxide, mancozeb, chlorothalonil and dithianon), as well as six fungicides with specific modes of action (fluopyram, boscalid, fluazinam, tebuconazole, azoxystrobin and pyraclostrobin) in raspberry spur blight (Didymella applanata) control were carried out in the seasons 2014 and 2016. The experiments were conducted as a randomized block design with four replicates in a commercial raspberry orchard in the locality Tresnjevica (Arilje) in western Serbia. All fungicides were applied preventively, four times until the beginning of harvest and once after harvest. The effects of the products tested were assessed three weeks after the last fungicide application according to the intensity of cane infection. Disease severity in control (untreated) plots were 53.7 (2014) and 76.3% (2016). In both years, the highest efficacy was achieved by tebuconazole (96.3 and 99.6%), followed by fluopyram (95.7 and 99.3%) and boscalid (94.7 and 95.9%). The broad-spectrum multi-site fungicides mancozeb, chlorothalonil, copper hydroxide and dithianon were effective against D. applanata and they reduced disease severity significantly, in comparison with the untreated plots. The efficacy of these compounds was between 64.4 and 81.7%. Conversely, azoxystrobin, pyraclostrobin, and fluazinam showed very low efficacy (13.7-37.8%) in control of raspberry spur blight.

Effect of Two Biological Formulations Based onBacillus subtilisandPseudomonas fluorescenson Control ofDidymella applanata, the Causal Agent of Red Raspberry Cane Spur Blight

In vitroandin vivostudies were conducted to estimate the efficacy of the two microbial formulations based onBacillus subtilisCohn. andPseudomonas fluorescensMig. on the fungusDidymella applanata(Niessl.) Sacc., the causal agent of red raspberry (Rubus idaeusL.) spur blight.In vitro, both bacteria reduced the growth ofD. applanata. In inoculation experiments with raspberry canes in two cultivars with different susceptibility toD. applanata, these antagonistic bacteria suppressed fungal development by reducing the lesions area and the number ofD. applanatafruiting bodies. Field trials of two biological formulations under natural conditions showed a significant suppression of the disease.B. subtilisandP. fluorescensincluded in the formulations revealed antagonistic activity towardsD. applanatathat depended on the red raspberry cultivar and weather conditions. In all cases,B. subtilisshowed better results thanP. fluorescensin biocontrol of the raspberry spur blight. This study demonstrated for the first time the ability of the biocontrol agentsB. subtilisandP. fluorescensto suppress red raspberry cane spur blight, a serious worldwide disease.

Toxicity of mancozeb, chlorothalonil, captan, fluopyram, boscalid, and difenoconazole to Didymella applanata isolates from Serbia

Field isolates of Didymella applanata, the causal agent of spur blight of raspberry, were evaluated in vitro for their sensitivity to mancozeb, chlorothalonil, captan, fluopyram, boscalid and difenoconazole. A total of 10 isolates, collected during 2013 at five localities in the major raspberry growing region in Serbia, and characterized as copper hydroxide, dithianon, and tebuconazole (sensitive), pyraclostrobin (sensitive or highly resistant) and fluazinam (sensitive or moderately resistant), were used in this study. The EC50 values for the isolates ranged from 1.33 to 2.88 mg L−1 for mancozeb, from 3.18 to 6.65 mg L−1 for chlorothalonil, from 15.75 to 24.69 mg L−1 for captan and from 1.80 to 8.20 mg L−1 for fluopyram. The narrowest range of EC50 values was recorded for difenoconazole (0.23–0.49 mg L−1), whereas the widest range was obtained for boscalid (4.49–49.25 mg L−1). The calculated resistance factors showed that all D. applanata isolates were sensitive to mancozeb, chlorothalonil, captan, and difenoconazole. Four isolates were moderately resistant to boscalid, while three of them were also moderately resistant to fluopyram. This finding of moderately resistant isolates to these SDHI fungicides indicates a possible cross-resistance which should be clarified in further investigations.

Characterisation of Gene H in Red Raspberry: Explaining its Role in Cane Morphology, Disease Resistance and Timing of Fruit Ripening

The Gene H region on raspberry linkage group 2 is an interesting region associated with a number of diverse traits. Cane pubescence is determined by Gene H and cultivars and selections with fine hairs (pubescent canes) are more resistant to cane botrytis and spur blight than non-hairy ones. Gene H is the most significant marker in a QTL on Linkage Group (LG) 2 that control cane pubescence and disease resistances and has also been demonstrated to delay ripening. Gene H phenotype for disease resistance is now used as a visual marker in resistance breeding. This study set out to explain the role of Gene H by characterising gene content in this region through identifying and sequencing BAC clones spanning the region to explain the phenotypic effects on cane hairiness, disease resistance and timing of ripening. This has allowed us to propose that PDF2/GLABROUS2 is Gene H and has also provided an insight into the effects the region has on ripening and disease resistance.

Control of Didymella applanata in raspberry orchards using new organic fungicides during vegetacion

Raspberry cane decay disease are the major problem in its production by reducing yield and lifetime of orchards. This disease cause a several disease-causing agents, and the most important is Didymella applanata, causal agent of raspberry spur blight. With regard to the biology of the pathogen fungicide use postharvest is not efficient enough because pat­hogen can infect raspberry far earlier. Therefore, the aim of this study is testing the efficacy of newer organic fungicides applied before and after the harvest raspberries and mutual comparison thereof on biological efficacy. The results show that the tested fungicides ex­hibited very high efficacy against D. apllanata on the raspberry leaves and the canes (from 83.0 - 96.5%).

FIELD EFFICACY OF FUNGICIDES AND BIOFUNGICIDES IN THE CONTROL OF SPUR BLIGHT OF RASPBERRIES IN SERBIA

efficacy of five conventional fungicides and two biofungicides was evaluated during 2009 and 2010 in one locality in Serbia where a strong epidemic of the target disease was expected. The following materials were tested: Acanto Plus, applied at 1.0 L/ha (picoxistrobin + ciproconazol, DuPont); Amistar Extra, applied at 1.0 L/ha (azoxystrobin + cyproconazole, Syngenta); Folicur EM 50-WP, applied at 2.5 kg/ha (tolylfluanid + tebuconazole, Bayer CropScience); F-Stop, applied at 10.0 L/ha (Bacillus subtilis, Bio-eko centar); Polyversum, applied at 1.0 kg/ha (Pythium olygandrum, Biopreparaty); Signum (boscalid + pyraclostrobin, BASF); and Switch 62.5-WG, applied at 1.0 kg/ha (fludioxonil + cyprodinil, Syngenta). The trials were arranged as randomized plots (10 m long rows), replicated four times with 90-100 plants/plot. The mean percentage values of disease control were calculated from the assessments made towards the end of the trials, when differentiation between treatments was most obvious. Data were analysed by one-way completely randomized ANOVA, and the comparison of means was performed by using Duncan’s test. The infection of raspberry canes in untreated control plots was 2.47 (2009) and 3.82 (2010) (expressed as a class of cane infection). In both years, biofungicides F-Stop (7.98 and 11.16%) and Polyversum (14.19 and 16.94%) exhibited the lowest efficacy among the tested products. Acanto Plus, Amistar Extra, Folicur EM 50-WP, Signum and Switch 62.5-WG were effective against the spur blight pathogen and they significantly reduced the disease severity compared with the untreated plots. Among the tested conventional fungicides, Acanto Plus (81.29 and 87.63%) and Switch 62.5-WG (82.28 and 85.29%) showed the highest efficacy in all trials. There was no statistically significant difference in the efficacies of the tested conventional fungicides.

High Tunnel and Open Field Production of Floricane- and Primocane-fruiting Raspberry Cultivars

Identical trials were conducted in a multibay high tunnel and an adjacent open field in southwestern Michigan to compare primocane-fruiting cultivars (Autumn Britten, Caroline, Chinook, Heritage) and floricane-fruiting cultivars (Canby, Encore, Heritage, Nova) of red raspberry (Rubus idaeus). Floricane-fruiting plots of ‘Heritage’ were pruned to produce fruit on floricanes and primocanes (double cropping). The most productive cultivars in both environments were ‘Nova’ and ‘Canby’ (floricane) and ‘Caroline’ and ‘Heritage’ (primocane). These cultivars produced annual yields of 5.5 kg·m−1 row in the tunnel and 2.5 kg·m−1 row in the field. The order of primocane harvest (earliest to latest) was the same in the tunnel and field: ‘Autumn Britten’, ‘Caroline’, ‘Chinook’, and ‘Heritage’. Cultivars with the greatest average berry weight in the tunnel and field were Encore and Nova (floricane) and Autumn Britten and Caroline (primocane). ‘Chinook’ and ‘Autumn Britten’ tended to have the highest incidence of gray mold (Botrytis cinerea) of primocane-fruiting cultivars, but incidence was similar in floricane cultivars. Overall mold incidence was 1% in the tunnel and 13% in the field. Leaf spot (Sphaerulina rubi), cane anthracnose (Elsinoe veneta), spur blight (Didymella applanata), and botrytis cane blight (B. cinerea) were common in the field but absent in tunnel. Phytonutritional analyses of primocane fruit indicated that genotype differences were not consistent across the two environments. Relative cultivar characteristics (harvest season, yield, berry quality) were similar in the field and tunnels, but the tunnel environment tended to increase plant vigor, yield, and fruit quality and suppress several diseases.

Functional Markers for Red Raspberry

Primers to 43 genes, including those involved in the phenylpropanoid and volatile pathways, cell wall, ethylene and polyamine metabolism, and from Prunus linkage group (LG) 6 were tested in red raspberry (Rubus idaeus) cultivars Latham and Glen Moy, and 40 were polymorphic. Thirty-seven genes were subsequently mapped in the ‘Latham’ × ‘Glen Moy’ population and were placed across all seven Rubus LG. This brings to 97 the total number of genic markers mapped in this Rubus mapping population. Fifteen genes are associated with existing quantitative trait loci for ripening, cane diseases, including yellow rust (Phragmidium rubi-idaei), cane botrytis (Botrytis cinerea), spur blight (Didymella applanata), and cane spot (Elsinoe veneta) or fruit color in R. idaeus and can be used for identifying bacterial artificial chromosome clones for physical mapping studies. A cluster of four genes from Prunus LG6 mapped together to Rubus LG3, suggesting that there may be sufficient synteny between these Rosaceae over small genomic regions that can be exploited in future studies.

The Effect of Chitinase on Didymella applanata, the Causal Agent of Raspberry Cane Spur light

In vitro and in vivo studies were conducted to assess the efficacy of the two microbial chitinases Chi I (from Streptomyces sp.) and Chi II (from Serratia marcescens) on Didymella applanata (Niessl.) Sacc., the fungus which causes spur blight of raspberry (Rubus idaeus L.). D. applanata was isolated from canes of diseased raspberries in a plantation in Novosibirsk, Russia. In vitro, the effective concentration of Chi I that reduced the growth of D. applanata was 0.4 U/ml (p = 0.05), but Chi II had no influence on the growth of the fungus in medium. In inoculation experiments on raspberry canes, both chitinases at the rate 0.5 U/ml reduced fungal development. In plantation where canes were inoculated after spraying with chitinase, fruiting bodies of fungus failed to form in all enzyme treatments, whereas a significant number of these fungal fruiting bodies (12.8 per cm2) developed in control treatments lacking chitinases spraying. The chitinases reduced the size of lesions and limited the infection of internal tissues of canes. Field testing of Chi I under natural conditions showed a significant suppression of the independent spur blight. These studies form the basis for further evaluation of ecologically benign control measures for raspberry spur blight.

Mapping gene H controlling cane pubescence in raspberry and its association with resistance to cane botrytis and spur blight, rust and cane spot

Disease resistance is increasing in importance, as consumers require high-quality raspberry fruit at a time when chemical disease control is undesirable. Breeders have limited resources and rarely include a primary screen for each fungal disease. Marker-assisted breeding would facilitate the introduction of resistance into elite germplasm and breeding lines. An additional 20 simple sequence repeats have been added to the existing raspberry linkage map. Gene H, which determines cane pubescence (genotype HH or Hh), the recessive allele of which gives glabrous canes (genotype hh), has been mapped on to linkage group 2 and shown to be closely associated with resistance to cane botrytis and spur blight but not rust or cane spot. Other map regions on linkage groups 3, 5 and 6 associated with disease resistance are reported here.

Raspberry Variety Performance in Southern Michigan

Seven primocane-fruiting and 15 floricane-fruiting raspberry varieties (Rubus idaeus) were compared for three fruiting seasons on a loamy sand soil in southwest Michigan. The earliest primocane-fruiting varieties (`Autumn Bliss', `Autumn Britten', `Polana') began ripening 3 weeks before the standard variety, `Heritage'. `Autumn Bliss' was the most productive early primocane-fruiting variety. `Caroline' and `Dinkum' ripened about 1 week earlier than `Heritage', and `Ruby' was 2 days later. `Caroline' was the most productive of this group and also had large fruit that were somewhat resistant to rot caused by Botrytis cinerea. `Caroline' also received the greatest leaf feeding from rosechafer beetles (Macrodactylus subspinosus). Most primocane-fruiting varieties were fairly resistant to leaf spot (Sphaerulina rubi), while `Dinkum' was highly susceptible to spur blight (Didymella applanata). Floricane-fruiting varieties were evaluated based on fruit production and quality as well as winter injury to canes, disease resistance, and feeding injury from two-spotted spider mites (Tetranychus urticae). The floricane-fruiting varieties showing minimal winter injury were `Boyne', `Killarney', `Latham', `Nova', and `Prelude'. `Canby', `Encore', `Glen Ample,', `Qualicum', `Reveille', `Titan', and `K 81-6' were moderately hardy; while `Tulameen', `Malahat', and `Lauren' were not hardy enough for this location. `Reveille', `Killarney', `Boyne', and `Prelude' were the most productive floricane-fruiting varieties. `Nova' and `Qualicum' had low levels of botrytis rot. `Nova' was most resistant to leaf spot and also had resistance to spur blight. Injury from mites was greatest on `Glen Ample' and lowest on `Malahat', `Prelude', `Qualicum', and `Tulameen'. `Caroline' (primocane-fruiting), `Prelude', and `Nova' (floricane-fruiting) were promising newer varieties.

Evaluation of the effects of biological preparations on phytopathogenic fungi Didymella applanata and Botrytis cinerea

Fungicidal and fungistatic effects of biological preparations involving bacteria of the genera Pseudomonas and Bacillus and fungi of the genus Chaetomium on phytopathogenic fungi Didymella applanata and Botrytis cinerea were evalauated. All the biological preparations under study inhibited the growth of colonies of the fungi; however, the degree of the inhibition depended on the nature of each particular microorganism and the concentration of each particular preparation. The preparation containing Bacillus subtilis at a concentration of 0.2% effected maximum suppression of B. cinerea (the diameter of the colonies decreased sevenfold). The preparations containing bacteria of the genus Pseudomonas and fungi of the genus Chaetomium were most efficient in suppressing D. applanata. The preparations containing B. subtilis and Chaetomium spp. showed promise as agents against simultaneous development of spur blight and Botrytis blight.

CONTROL OF RASPBERRY AND BLACKCURRANT DISEASES BY TOLYLFLUANID

The effectiveness of tolylfluanid (Euparen Multi) for control of grey mould (Botrytis cinerea) of raspberry and blackcurrant and spur blight (Didymella applanata) of raspberry was evaluated in field experiments during 1995-2000. Euparen Multi treatment provided good control of grey mould. On raspberries, its effectiveness varied from 65% to 95% and was on the same level or only slightly lower than the best botryocide procymidone (Sumilex 500 SC). The efficacy of tolylfluanid in control of grey mould on blackcurrant plantations was also similar to procymidone treatments. On blackcurrant cv. 'Ojebyn', tolylfluanid additionally reduced white pine blister rust (Cronartium ribicola) and septoria leaf spot (Septoria ribis) diseases. Spur blight and grey mould of raspberry canes were difficult to control on the very susceptible cultivar 'Malling Promise' and the efficacy of tolylfluanid treatments varied depending on the season.

WHAT'S GOING ON IN THE WORLD OF RUBUS BREEDING?

WHAT'S GOING ON IN THE WORLD OF RUBUS BREEDING?

Field testing of BACTICIDE ® , PHYTOVERM ® and CHITINASE for control of the raspberry midge blight in Siberia

Three products based on compounds of biological origin were tested for their ability tocontrol the raspberry midge blight in theSiberian region of Russia. Bacillusthuringiensis subsp. israelensis(BACTICIDE®) and Streptomycesavermitilis metabolites (PHYTOVERM®) were used against Thomasiniana theobaldi (ageneral member of the midge blight) andCHITINASE was used against fungi (mainly Didymella applanata) associated with T. theobaldi. The BACTICIDE®(0.2%) and PHYTOVERM® (0.2%) sprays caused a 2-fold decrease in midge blight severity and the sameeffect was obtained with chemical insecticides.The CHITINASE (1%) spray caused a 4-folddecrease in the severity of midge blight. Inaddition, CHITINASE and PHYTOVERM®caused a significant suppression of theindependent spur blight. These studies form thebasis for further evaluation of ecologicallysafe control of the raspberry midge blight.