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Tuberculina sp.,苹果锈病菌的一种重寄生菌 总被引：1，自引：0，他引：1
苹果锈病(Gymnosporangium yamadai)在我国大部分苹果产区均有发生，在一些地区发病严重。该病造成叶片枯斑，早期落叶，削弱树势，影响产量。该病长期采用化学农药或砍伐其转主寄主柏科植物进行防治，导致杀伤天敌，有益生物种类减少，果园生态群落结构恶化，果品中农药残留量增加。由于该锈菌同时在转主寄主柏科植物上寄生危害，也给药剂防治及防治效果带来不利影响。利用重寄生菌防治植物病害是生物防治的方法之一。植物锈菌的重寄生菌研究，国内外已有报道。但苹果锈病菌的自然重寄生菌尚未见报道。本文是苹果锈病菌的自然重寄生现象及重寄生菌的研究报道。 相似文献
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粟杆蝇幼虫为害谷子常造成枯心或不实。此虫一年发生二代,部分一代。以老熟幼虫在5—10厘米土层中越冬。成虫于6月中旬出現,6月末达盛期,每雌产11—41卵,产卵于粟杆的基部。粟杆蝇的发生为害与湿度有密切关系,交尾、产卵、幼虫孵化、以及侵入粟茎均需高湿。田間枯心率与当年6月份降雨量的相关系数为0.71(P<0.01),相关显著。在晚播、高肥、密植的条件下,枯心发生严重。谷子品种、生育速度均与被害程度有关。在粟田雌蝇出現高峯期噴5％DDT与0.5％666等量混合粉剂,有良好的防治效果。 相似文献
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玉米苗期干腐病重发生原因与防治技术 总被引：2，自引：0，他引：2
玉米干腐病是江华县玉米的常见病害。自1994年玉米苗期重发生之后,多年来一直发生较轻。2004年3月中、下旬,此病再次在本县22个乡(镇)普遍发生,局部地方成灾。其中大圩镇病田率100%,病株率30%～50%,加权平均死苗率21.6%,部分田块玉米死苗或缺苗的现象极为严重。干腐病已危及到玉米生产安全,影响了农民增收。为深入了解玉米苗期干腐病发生的实际情况,笔者对发病较重的乡(镇)进行了田间实地调查,从多方面分析其重发生原因,探讨了防治对策。1重发生原因分析1.1气候因素根据江华县气象局资料,受冷空气影响,2004年3月18～25日连续8d日平均气温在1… 相似文献
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三种防腐剂对马铃薯薯块干腐病菌的毒力及抑制作用 总被引：1，自引：0，他引：1
马铃薯干腐病是目前马铃薯贮藏期间发生较严重的一种病害,已成为影响马铃薯贮藏保鲜的瓶颈问题之一。为筛选出施用简便、安全高效且能取代液体类毒性强的防腐剂,试验对二氧化氯、仲丁胺和过氧乙酸三种熏蒸型防腐剂进行了室内毒力测定和抑制效果评价。结果表明：该三种防腐剂对马铃薯干腐病具有不同的抑制活性,其中仲丁胺对马铃薯干腐病的抑菌效果最佳,其毒力回归式为y=3.608 7+7.500 8x,EC50为0.202 8 μg/mL。通过3种防腐剂的体内效果试验,结果表明：在低温条件下,3种防腐剂处理均不同程度地降低了马铃薯块茎的发病率,其中以仲丁胺控制效果最佳,95 μg/kg 浓度处理可明显降低接种马铃薯薯块的发病率和病斑扩展速度。因此可以推断仲丁胺是防治马铃薯干腐病的理想药剂之一。 相似文献
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近年,在矮砧密植苹果园发现苗木栽植后幼树主干上的枝干轮纹病发生严重,急需有效的防治方法。针对生产中的需求,本研究对幼树枝干轮纹病的防治方法进行了探索,结果显示:用乳胶液配制的戊唑·多菌灵·乙膦铝混合剂对枝干轮纹病防治效果显著高于同种药剂的水溶液,对剪锯口枝干轮纹病防治效果可达63.7%~100%,是药剂水溶液防效的2~3倍;生长季施用2次,对枝干轮纹病病斑的铲除率为45.2%,是药剂水溶液防效的9.6倍以上。结果表明,戊唑·多菌灵·乙膦铝乳胶液对枝干轮纹病防治效果显著,可以用于苗木剪锯口的防护,以及新建果园中幼树枝干轮纹病的治疗。研究结果为生产中幼树枝干轮纹病的防治提供了有效的方法。 相似文献
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R. S. Utkhede E. M. Smith 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(5):507-510
The effect of microjet, drip, and two durations of sprinkler irrigation systems on phytophthora crown and root rot of apple trees was examined under field conditions. This eight year study indicates that crown and root rot caused byPhytophthora cactorum was most severe where young MM. 106 rootstock trees were watered by microjet irrigation for 2.3 h each day. There was no difference in infection byP. cactorum when trees were irrigated either by drip or sprinkler irrigation systems. The MM.106 apple rootstock trees watered by drip irrigation for 2.6 h each day were least affected by phytophthora crown and root rot. 相似文献
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Mulberry twigs were inserted into the soil as bait to detect Rosellinia necatrix at an early stage of tree infection in the orchard. R. necatrix was frequently trapped on twigs near the trunk base at soil depths of 6–20 cm within 10–20 days in May–July, suggesting that
the incubation period was dependent on soil temperature. Subsequently, we inserted twig in the soil around healthy-looking
trees in naturally infested orchards. R. necatrix was trapped from 80.0% of Japanese pear and 75.0% of apple trees that later proved to be infected. This bait twig method
facilitated quicker diagnosis of white root rot on Japanese pear and apple at early stages of infection and can be used to
detect recurrence of the fungus after fungicide treatment. 相似文献
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R. F. DE BOER F. C. GREENHALGH K. G. PEGG P. E. MAYERS T. M. LIM S. FLETT 《EPPO Bulletin》1990,20(1):193-197
Treatments with a partially neutralized formulation of phosphorous acid containing potassium phosphite were assessed for control of Phytophthora diseases in subtropical and temperate crops in Australia. In Queensland, trunk injections of phosphite (10% solution) controlled severe root rot (Phytophthora cinnamomi) of avocado trees and resulted in the recovery of trees. Single pre-harvest sprays (2.5 kg ha-1) of phosphite controlled root and heart rot (P. cinnamomi) of pineapples. Foliar sprays of phosphite (64 g per tree) controlled root rot (P. nicotianae var. parasitica) and trunk canker (P. citrophthora) of mandarin trees. In Victoria, a foliar spray of phosphite (300 g ha-1) reduced root rot (P. clandestina) of subterranean clover and increased dry matter by 1.96 to 5.11 t ha-1. Trunk injections of phosphite (10% solution) controlled trunk rot (P. cactorum) of peach trees and foliar sprays (10 kg ha-1) reduced severity of root rot (P. nicotianae var. nicotianae) of tomatoes. 相似文献
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Rajeshwar S. Utkhede 《Pest management science》1987,19(4):289-295
Four fungicides were evaluated as combined soil drench and trunk treatments for the control of crown rot, caused by Phytophthora cactorum, in naturally infected apple trees. In a 3-year preliminary study, metalaxyl at 1 and fosetyl-aluminium at 8 g a. i. per tree, applied twice a year, prevented death of infected trees showing only initial, but not more severe, symptoms of crown rot. This indicates that these fungicides have the ability to arrest further symptom development in naturally infected trees if they are treated as soon as symptoms appear. Healthy trees remained free of infection if they were treated with these fungicides, suggesting a preventative action. Repeated bi-annual application of metalaxyl or fosetyl-aluminium should be sufficient to prevent the loss of trees to crown rot. 相似文献
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Rajeshwar S. Utkhede 《Pest management science》1984,15(3):241-246
The mycelial growth of Phytophthora cactorum on corn meal agar was completely inhibited by metalaxyl or mancozeb at 50 or 100 μg ml?1, but not by fosetyl-aluminium at the same concentrations. Soil drenches with metalaxyl, followed by metalaxyl+mancozeb, around the base of naturally infected trees under orchard conditions, prevented the growth of P. cactorum in the infected bark of the tree. Soil drenchs with metalaxyl, followed by metalaxyl+mancozeb, also prevented the infection of apple trees with P. cactorum under orchard conditions. The trunk circumference and spur length were not significantly affected by any of the fungicide treatments in all the trials over 2 years, except in one of the four orchards used in the study. Soil drench with metalaxyl alone, or followed by metalaxyl+mancozeb, may provide an effective control method for crown rot of apple trees. 相似文献
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Canker and wood rots are economically important preharvest diseases of lemons in south-western Arizona, where commercial lemon production is concentrated. However, the aetiology and epidemiology of canker and wood rots are not well understood. This study comprised a large survey of canker and wood rot incidence and severity in Arizona and the characterization of fungal species associated with the disease. A total of 5431 trees with ages ranging from 1 to 20 years old in 10 lemon orchards were surveyed from 2018 to 2020. Our survey results revealed that canker and wood rot occurred in all 10 lemon orchards studied. Canker and brown rots of twigs, branches, and trunks were the most prevalent symptoms of affected trees ranging from 1 to 20 years old. In contrast, canker and white rots of twigs and branches were observed mostly on 1- to 5-year-old trees. Disease incidence for both diseases was less than 2% on 1- and 2-year-old trees. Brown rot increased significantly in older trees, ranging from 62.9% to 100%. Fungi were isolated from canker and wood rot samples and identified based on morphological characters and DNA sequences. Fomitopsis meliae and Hypoxylon macrocarpum were the primary canker and wood rot pathogens isolated from the surveyed orchards, at frequencies of 89% and 11%, respectively. In pathogenicity tests, both fungi were capable of causing canker and wood rots on lemon cv. Lisbon branches and the necrotic length caused by F. meliae was twofold greater than that caused by H. macrocarpum. 相似文献
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Mazzola M 《Phytopathology》1997,87(6):582-587
ABSTRACT Rhizoctonia spp. were isolated from the roots of apple trees and associated soil collected in orchards located near Moxee, Quincy, East Wenatchee, and Wenatchee, WA. The anastomosis groups (AGs) of Rhizoctonia spp. isolated from apple were determined by hyphal anastomosis with tester strains on 2% water agar and, where warranted, sequence analysis of the rDNA internal transcribed spacer region and restriction analysis of an amplified fragment from the 28S ribosomal RNA gene were used to corroborate these identifications. The dominant AG of R. solani isolated from the Moxee and East Wenatchee orchards were AG 5 and AG 6, respectively. Binucleate Rhizoctonia spp. were recovered from apple roots at three of four orchards surveyed and included isolates of AG-A, -G, -I, -J, and -Q. In artificial inoculations, isolates of R. solani AG 5 and AG 6 caused extensive root rot and death of 2- to 20-week-old apple transplants, providing evidence that isolates of R. solani AG 6 can be highly virulent and do not merely exist as saprophytes. The effect of binucleate Rhizoctonia spp. on growth of apple seedlings was isolate-dependent and ranged from growth enhancement to severe root rot. R. solani AG 5 and AG 6 were isolated from stunted trees, but not healthy trees, in an orchard near Moxee, WA, that exhibited severe symptoms of apple replant disease, suggesting that R. solani may have a role in this disease complex. 相似文献
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J. DVORCÅK 《Weed Research》1968,8(1):8-13
Summary. In loamy soil with a low humus content (0·8% organic carbon) simazine at a concentration of 2'5 ppm reduced growth of shoots, roots and trunk diameter in 1-year-old scions of five apple varieties on M IX rootstock. The most susceptible was Cox's Orange Pippin; 5 ppm was lethal for this variety only. In experiments with vertically divided pots, where one part of the root system developed in soil with simazine (2–5 ppm and 5–0 ppm for apple and 5·0 ppm for plum) and the other part in simazine-free soil, there was less effect on shoot growth and less leaf damage than where all the soil contained simazine. Growth of that part of the root system in soil containing simazine was stimulated. 相似文献