Control of blue mold (Penicillium expansum) by fludioxonil in apples (cv Empire) under controlled atmosphere and cold storage conditions

A reduced risk fungicide, fludioxonil, was tested for its efficacy against blue mold caused by thiabendazole-resistant and -sensitive Penicillium expansum (Link) Thom in apples under three storage conditions. In a co-treatment, fludioxonil and inoculum were applied together to test the protective activity of the fungicide on wounds that had been aged for 1 or 2 days. The fungicide was also tested for its curative activity in post-inoculation treatment on apples that had been inoculated for 1 or 2 days. Fludioxonil was very effective as co-treatment and as post-inoculation treatment. At a concentration of 300 mg litre(-1), fludioxonil gave complete control of post-harvest blue mold caused by the thiabendazole-resistant and -sensitive P expansum for 105 days in controlled atmosphere (CA) storage at 2 (+/-1) degrees C, for 42 days in common cold storage at 4 (+/-1) degrees C and also in a shelf-life study for 6 days at 20 (+/-1) degrees C. Comparison on the effect of fludioxonil in CA storage and common cold storage showed that higher concentrations of fungicide were needed in cold storage than in CA storage. Fludioxonil at a concentration of 450 mg litre(-1), gave 98 and 92% control of blue mold of apples in the simulated shelf-life studies after CA and common cold storages, respectively. Fludioxonil has a potential to be incorporated in the fungicide resistance management strategies for control of blue mold in apples stored for 105 days.     

Nutritional Enhancement of Biocontrol Activity of Candida sake (CPA-1) against Penicillium expansum on Apples and Pears

Pome fruits are poor in nitrogenous compounds and the addition of nitrogen can improve colonisation of the fruits by antagonists. Twenty-two nitrogenous compounds were evaluated for their effect on Candida sake (CPA-1) growth in vitro. Ten compounds that induced greater growth were applied with the antagonist to wounded fruits to evaluate their effect on enhancing control of Penicillium expansum. Calcium chloride and 2-deoxy-D-glucose were also tested. L-serine and L-aspartic acid enhanced biocontrol by C. sake against P. expansum on apples. On apples and pears, ammonium molybdate, calcium chloride and 2-deoxy-D-glucose improved the capacity of the antagonist to control P. expansum. The addition of ammonium molybdate at 1 mM allowed C. sake to be used on apples and pears at a lower concentration without diminishing control. Similar results were observed with the addition of calcium chloride to the antagonist. 2-deoxy-D-glucose at 6 and 18 mM enhanced biocontrol on pears by over 81%, but on apples the improvement of biocontrol was observed only at 6 mM. In cold storage, the combination of ammonium molybdate and C. sake completely eliminated the incidence of blue mould on pears, and reduced its severity and incidence by more than 80% on apples.     

Improved Control of Postharvest Decay of Pears by the Combination of Candida sake (CPA-1) and Ammonium Molybdate

ABSTRACT The potential enhancement of Candida sake (CPA-1) by ammonium molybdate to control blue and gray mold caused by Penicillium expansum and Botrytis cinerea, respectively, on Blanquilla pears was investigated. In laboratory trials, improved control of blue and gray molds was obtained with the application of ammonium molybdate (1, 5, 10, and 15 mM) alone or in combination with C. sake at 2 x 10(6) or 2 x 10(7) CFU ml(-1) on Blanquilla pears stored at 20 degrees C. In semicommercial trials at 1 degrees C for 5 months, the efficacy of C. sake at 2 x 10(6) CFU ml(-1) on reducing P. expansum and B. cinerea decay was enhanced more than 88% with the addition of ammonium molybdate 5 mM in the 1999-2000 season. In two seasons, the performance C. sake at 2 x 10(6) CFU ml(-1) plus ammonium molybdate was similar to or greater than that of C. sake at 2 x 10(7) CFU ml(-1). Similar control of blue mold was obtained on pears stored under low oxygen conditions. The preharvest application of ammonium molybdate did not reduce postharvest blue mold decay. The population of C. sake on pear wounds significantly decreased in the presence of ammonium molybdate 1 and 5 mM at 20 and 1 degrees C.     

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.     

Effect of apple cultivars and storage periods on the virulence of Neofabraea spp.

Bull’s eye rot is a typical quiescent postharvest apple disease in major fruit-growing areas. The susceptibility of different apple cultivars to Neofabraea spp. (N. vagabunda and N. malicorticis) was assessed, with Granny Smith showing the most resistance and Cripps Pink the most susceptibility. To assess the factors involved in conidial germination, Neofabraea spp. were grown on crude protein extracts (CPEs) collected from apple fruits at different storage periods. Fungal germ tube growth rate and pathogenic enzyme (cellulase and xylanase) activity were assessed. Results showed that CPEs collected after 2 and 4 months of storage progressively stimulated conidial germination and germ tube elongation, while a lesser effect was observed from CPEs after 1 month of storage. Xylanase proved to be the main degrading enzyme secreted by all the isolates, while cellulase was produced only by N. vagabunda isolates. Overall, the isolate ID02 was the most virulent, based on more rapid germ tube elongation and greater activity of the lytic enzymes.     

Biological control of potato soft rot caused by Dickeya solani and the survival of bacterial antagonists under cold storage conditions

Dickeya and Pectobacterium are responsible for causing blackleg of plants and soft rot of tubers in storage and in the field, giving rise to losses in seed potato production. In an attempt to improve potato health, biocontrol activity of known and putative antagonists was screened using in vitro and in planta assays, followed by analysis of their persistence at various storage temperatures. Most antagonists had low survival on potato tuber surfaces at 4 °C. The population dynamics of the best low-temperature tolerant strain and also the most efficient antagonist, Serratia plymuthica A30, along with Dickeya solani as target pathogen, was studied with TaqMan real-time PCR throughout the storage period. Tubers of three potato cultivars were treated in the autumn with the antagonist and then inoculated with D. solani. Although the cell densities of both strains decreased during the storage period in inoculated tubers, the pathogen population was always lower in the presence of the antagonist. The treated tubers were planted in the field the following growing season to evaluate the efficiency of the bacterial antagonist for controlling disease incidence. The potato endophyte S. plymuthica A30 protected potato plants by reducing blackleg development on average by 58.5% and transmission to tuber progeny as latent infection by 47–75%. These results suggest that treatment of potato tubers with biocontrol agents after harvest can reduce the severity of soft rot disease during storage and affect the transmission of soft rot bacteria from mother tubers to progeny tubers during field cultivation.     

纳他霉素防治苹果贮运期病害的初步研究

采用生长速率法测定了纳他霉素对苹果轮纹病菌、苹果黑星病菌、苹果黑斑病菌、苹果腐烂病菌的室内毒力,结果表明,该制剂对各病菌的抑制有效中浓度EC50分别为18.44、49.43、32.08、29.87μg/mL,并用病原菌感染方法测定了制剂对贮运期苹果的实物防治效果。纳他霉素浓度为200μg/mL的制剂各处理组在10d、14d、18d的防效分别达到52.91%、55.02%、54.12%,显著高于多菌灵对照的防效。     

灰黄青霉CF3对马铃薯土传病原真菌的拮抗性及其促生作用

为探索灰黄青霉Penicillium griseofulvum CF3对马铃薯土传病害病原真菌立枯丝核菌Rhizoctonia solani、茄病镰刀菌Fusariumsolani、硫色镰刀菌F.sulphureum及大丽轮枝菌Verticillium dahliae的拮抗性及对马铃薯的促生作用,采用菌丝生长速率法和甜瓜种子发芽法分别研究了CF3发酵液对病原菌菌丝的抑制作用、对立枯丝核菌微菌核形成的影响及其发酵液的促生作用,并采用盆栽试验法研究了CF3孢子粉对马铃薯植株的促生作用及对抗逆性的影响.CF3发酵滤液对4株病原真菌菌丝生长的抑菌率达53％～72.1％,对立枯丝核菌微菌核的抑制率达36.8％～100％,并显著促进甜瓜种子胚根、胚轴生长.灰黄青霉孢子粉拌土和包衣接种均能促进马铃薯植株生长并增强植株的抗逆性.其中,拌土接种使马铃薯地上植株鲜重和多酚氧化酶活性较对照分别增加38.3％和9％,丙二醛含量降低28.8％.研究表明灰黄青霉CF3对连作马铃薯常见土传真菌病害有较强的生防潜力,对马铃薯具有良好的促生作用.     

生物源杀菌剂与化学杀菌剂协调防控黄瓜病害

本文研究枯草芽孢杆菌Bacillus subtilis BAB-1水剂、解淀粉芽孢杆菌B.amylololiquefaciens SAB-1水剂、大花旋覆花内酯乳油与化学杀菌剂交替或混合使用对温室黄瓜病害发展的影响.寿光试验包括以下处理:交替或混合喷施50%啶酰菌胺WG、68.75%氟吡菌胺·霜霉威SC的桶混液、60%唑醚·代森联WG、40%嘧霉胺SC、50%烯酰吗啉WP、10%苯醚甲环唑WG、69%烯酰·锰锌WP、68.75%噁唑·锰锌WG、52.5%噁唑·霜脲氰WG等不同作用机理和防治谱的化学杀菌剂;混施生防菌剂BAB-1水剂、SAB-1水剂及68.75%氟吡菌胺·霜霉威SC、50%烯酰吗啉WP、25%双炔酰菌胺SC、25%吡唑醚菌酯EC等对霜霉病特效化学杀菌剂;将不同化学杀菌剂桶混液与BAB-1水剂、SAB-1水剂和化学杀菌剂桶混液交替喷施.其对黄瓜霜霉病的防效分别为94.5%、92.3%和93.6%,对黄瓜白粉病分别为90.7%、89.9%和90.4%,对灰霉病的防效分别为69.3%、85.6%和85.7%,每种病害的病害发展曲线下面积(AUDPC)相当.在定州试验中,化学杀菌剂与SAB-1混施对白粉病的防效(84%)明显高于其与BAB-1混施的防效(72.8%),对灰霉病的防效(61.3%)明显低于后者的防效(95.1%),与SAB-1、BAB-1混施后对白粉病、灰霉病及霜霉病防效分别为90.2%、89.3%和92.6%.在保定郊区试验中,将大花旋覆花内酯乳油与化学杀菌剂及BAB-1水剂、SAB-1水剂交替喷施显著降低霜霉病、白粉病及灰霉病的严重度及AUDPC,对其防效分别为83.5%、87.4%和88.5%,AUDPC分别为219、352和249,延缓了3种黄瓜病害的发展.     

贮藏期蒜薹表面真菌群落组成分析

蒜薹作为一种传统常年供应的蔬菜深受喜爱,由于贮存时间长,贮存过程中会有多种真菌产生,导致蒜薹失去经济价值。本文通过提取贮藏期蒜薹表面真菌的基因组DNA,经Illumina平台对7个样本的ITS扩增子进行测序,共获得2 418 016条raw reads,51个OTUs。通过OTU物种注释和物种丰度聚类,优势真菌属组成为:青霉菌属Penicillium 81.08%,未知子囊菌15.13%,耐冷酵母Mrakia 1.74%,小球壳属Mycosphaerella 1.02%。青霉菌是贮藏蒜薹后期表面的主要真菌。     

Investigations on Oecophylla longinoda (Latreille) (Hymenoptera: Formicidae) as a biocontrol agent in the protection of cashew plantations

BACKGROUND: Cashew (Anacardium occidentale L.) has become a very important non‐traditional tree crop in Ghana. The crop is, however, attacked by sap‐sucking insects, particularly the mosquito bug, Helopeltis schoutedeni Reuter, the leaf‐footed bug, Pseudotheraptus devastans (Dist.), and the coreid bug, Anoplocnemis curvipes (F.), which feed on shoots, panicles and fruits. Their damage is characterised by withering of the latter. In Ghana, Oecophylla longinoda Latr. occurs in large numbers on cashew and other native plants, but little is known about its relationship with insect pests. The relationship between O. longinoda and shoot and panicle damage by sap‐sucking bugs and the effectiveness of O. longinoda as a biocontrol agent in the protection of cashew as compared with two chemical insecticides, lambda‐cyhalothrin (Karate^®) and cypermethrin + dimethoate (Cyperdim^®), were therefore investigated at Bole in the northern region of Ghana. RESULTS: There was a negative correlation between numbers of O. longinoda nests and pest damage. Trees treated with cypermethrin + dimethoate (969 mg AI mL^?1 tree^?1) and lambda‐cyhalothrin (100 mg AI mL^?1 tree^?1) recorded the smallest bug numbers, followed by O. longinoda. Trees infested by Oecophylla longinoda and trees treated with cypermethrin + dimethoate and with lambda‐cyhalothrin had less than 6% pest damage to shoots, panicles and fruits, while water‐sprayed trees recorded damage as high as 36.8% (shoots) in February, 32.9% (panicles) in February and 37.8% (fruits) in March. Cypermethrin + dimethoate again recorded the highest (485.0 kg ha^?1) nut yield, followed by O. longinoda (431.0 kg ha^?1), with water recording the lowest (93.0 kg ha^?1) nut yield. CONCLUSION: The results indicate that O. longinoda can be used to control some sucking bugs as effectively as some insecticides. Copyright © 2008 Society of Chemical Industry     

Effects of pesticides on mite predators (Acari: Phytoseiidae) and colonization of apple trees byTetranychus urticae

A 2-year survey of mite populations and pesticide use was carried out in Nova Scotia, Canada, in apple orchards where the two-spotted spider mite (Tetranychus urticae Koch) was the dominant phytophagous mite. Fungicides were the only class of pesticides that affected cumulative number ofT. urticae-days per leaf in tree canopies and colonization success — the ratio ofT. urticae-days to number of immigratingT. urticae caught in sticky bands on tree trunks. In 2000, increased numbers ofT. urticae-days in the tree canopy were associated with more frequent applications of ethylene bis-dithiocarbamate (EBDC) fungicides and with higher fungicide toxicity scores, which indicate cumulative level of suppression of the phytoseiid predatorTyphlodromus pyri Scheuten by all fungicide applications. Higher rates of colonization success were also associated with higher toxicity scores. EBDC’s applied in 2000 promotedT. urticae immigration as indicated by their counts on sticky bands. In 2000 and 2001, number ofT. pyri-days in the tree canopies was decreased by more frequent EBDC applications and by higher fungicide toxicity scores. Promotion ofT. urticae in tree canopies by EBDC’s was attributed to their toxicity toT. pyri. BothT. pyri and another phytoseiid,Amblyseius fallacis (Garman), were found in ground cover vegetation. Hence, increased immigration from the ground cover attributed to the toxicity of EBDC’s toT. pyri and, especially, toA. fallacis, which is a specialist predator of spider mites and an effective natural enemy ofT. urticae. http//www.phytoparasitica.org posting Sept. 13, 2006. Formerly, Atlantic Food and Horticulture Research Centre, now retired.     

冷藏对双尾新小绥螨捕食能力和繁殖力的影响

为探究双尾新小绥螨Neoseiulus bicaudus（Wainstein）的最佳贮藏温度和时间,选取双尾新小绥螨成螨于9℃和12℃下分别冷藏7、14、21、28和35 d,测定不同冷藏条件下双尾新小绥螨雌成螨的捕食能力和繁殖力。结果表明：冷藏后,除9℃冷藏21 d处理外,其他处理下双尾新小绥螨的捕食量、攻击系数、捕食能力、日最大捕食量以及对猎物的处理时间与对照之间均无显著差异,其中12℃冷藏21 d的攻击系数最高,为3.18,12℃冷藏28 d的处理时间最长,为0.14 d;当冷藏时间相同时,双尾新小绥螨于9℃冷藏后的攻击系数与12℃冷藏处理间无显著差异,但冷藏21 d和28 d后,9℃冷藏的处理时间显著短于12℃的处理时间;双尾新小绥螨冷藏一段时间后恢复正常温度,雌成螨产卵前期延长,最长为3.06 d,显著长于对照;雌成螨的平均寿命和产卵量显著降低,雌成螨寿命最长,为14.10 d,总产卵量最高,为18.98粒,均显著低于对照;当冷藏温度相同,不同冷藏时间处理的双尾新小绥螨雌成螨的寿命和产卵量无显著差异。冷藏时间相同时,12℃冷藏处理的雌成螨平均寿命和产卵量显著高于9℃冷藏处理。综上,双尾新小绥螨于12℃和9℃中冷藏0~35 d后均对双尾新小绥螨的捕食无影响,而12℃冷藏不同时间后对双尾新小绥螨雌成螨的寿命和繁殖影响相对较小。因此,建议双尾新小绥螨于12℃冷藏0~35 d。     

电子束检疫辐照处理对我国红富士苹果品质的影响

为探索电子束辐照在我国红富士苹果检疫处理中的应用可行性,本文研究了不同剂量的电子束辐照对我国红富士苹果色泽、硬度、失水率、可溶性固形物、酸度、还原型维生素C、蛋白质、脂肪以及氨基酸等营养品质的影响。结果表明,1 155 Gy及以上剂量的电子束辐照可导致苹果硬度显著下降;随着储存时间的延长,330 Gy剂量以上辐照组苹果的还原型维生素C含量明显高于对照组;低于1 650 Gy电子束辐照18 d后对红富士苹果的色泽、失水率、可溶性固形物、酸度、蛋白质、脂肪、氨基酸等品质没有影响。因此,本研究认为低于990 Gy的电子束辐照处理红富士苹果是可行的。     

低温贮藏对加州新小绥螨生物学特性和捕食能力的影响

为探究加州新小绥螨国内种群的最佳贮藏方法,在4、7、10℃下,以叶片+叶螨和花粉2种冷藏基质及不同冷藏时间为参试因子,研究了低温贮藏对其雌成螨存活、产卵和捕食的影响,并测试了其卵冷藏后的存活及发育情况。结果显示,温度、基质和时间3个因子均显著影响冷藏处理后加州新小绥螨雌成螨的存活率、产卵量和捕食率。在4、7、10℃下,以花粉为基质冷藏超过10 d后雌成螨存活率均低于50%,不适宜长期贮藏;以叶片+叶螨为基质冷藏分别超过20、25、30 d后雌成螨存活率显著降低,超过30 d后产卵前期较对照的1.05 d显著延长,分别达到3.07、3.14、2.29 d。在2种基质中,所有冷藏处理的单雌1周日均产卵量为1.55~2.96粒,均低于对照的2.97粒,且随冷藏时间的增加呈下降趋势;冷藏后雌成螨产卵期捕食率为每12 h 11.60~15.84头,均高于对照的11.60头。冷藏温度和时间显著影响卵的孵化率和发育历期,短期冷藏后孵化的雌螨比例与对照差异不显著。表明加州新小绥螨雌成螨适宜以叶片+叶螨为冷藏基质,短期冷藏的最适温度为4~7℃,长期冷藏最适温度为10℃;卵以4℃冷藏7 d最佳,在10℃下冷藏不宜超过2周。     

低温寒流天气对褐飞虱发生期发生量的影响观察

褐飞虱第５代是我市晚稻的主害代,常年５代,成虫盛期在９月中旬或下旬,而我市这一时期常出现低温寒流天气。为了解低温天气对褐飞虱发生期、发生量的影响,１９９７年,我们在褐飞虱回迁虫量大（因其迁入期与本地５代成虫期基本吻合,故称为５代）,并恰遇低温寒流天气...     

高温对芙新姬小蜂控制美洲斑潜蝇潜力的影响

为明确高温条件对芙新姬小蜂Neochrysocharis formosa(Westwood)成虫寿命以及行为的影响,以美洲斑潜蝇Liriomyza sativae Blanchard 2龄末至3龄初幼虫为寄主,在补充非寄主食物20%葡萄糖溶液的情况下,观察了芙新姬小蜂雌成虫在26、30℃和35℃3个温度下的寿命及对美洲斑潜蝇的取食致死数、叮蛰致死数、寄生致死数和总致死数。结果显示：与26℃相比,高温条件(30℃和35℃)下,单头雌虫的日均取食致死数、日均叮蛰致死数、日均寄生致死数、日均总致死数均显著升高,并在35℃达到最高值,分别为9.6、12.2、5.5头和27.3头。芙新姬小蜂雌成虫的寿命随着温度升高而显著缩短,26℃下的寿命(21.4 d)约为30℃下寿命(11.4 d)的1.9倍和35℃下寿命(9.6 d)的2.2倍。3个温度下雌成虫一生的取食致死数、叮蛰致死数、寄生致死数、总致死数均无显著差异,总寄主致死数均达230头以上。表明35℃高温对芙新姬小蜂控制美洲斑潜蝇的总潜力没有显著影响。     

农林复合对近地面微气候环境的影响

以渭北黄土区农林实践中发展最为迅速的核桃(Juglans regia)-小麦(Triticum aestivum)间作复合模式为研究对象,以两物种的单作系统为对照,讨论农林复合系统对近地面微气候环境的影响,为农林复合系统经营管理和模型的建立提供理论依据。结果表明,核桃-小麦间作降低了2—10月近地面气温和地温,期间气温平均值分别比核桃单作和小麦单作低0.66℃和0.97℃,期间地温平均值分别比核桃单作和小麦单作低0.71℃和1.41℃。核桃-小麦间作提高了11月至第2年1月近地面气温和地温,期间气温平均值分别比核桃单作和小麦单作高0.49℃和0.40℃,期间地温平均值分别比核桃单作和小麦单作高1.01℃和0.69℃。核桃-小麦间作各月近地面空气相对湿度均高于两单作系统,其全年平均值分别比核桃单作和小麦单作提高了14.33%和19.98%。核桃-小麦间作各月近地面平均风速和相对照度均低于两单作系统,其全年平均风速分别比核桃单作和小麦单作降低了26.32%和30.00%,全年平均相对照度分别比核桃单作和小麦单作降低了21.33%和45.93%。核桃-小麦间作浅层土壤湿度在4—5月低于两单作系统,在6—7月迅速升高,在7—9月高于两单作系统。核桃-小麦间作复合系统可以降低高温季节近地面的土壤温度、气温、风速和相对光强,这对降低土壤水分的无效蒸发具有重要意义。