Cashew (Anacardium occidentale L.) is the present leading currency earning crop in Tanzania, generating income to over 2.5 million farmers. Despite of its importance, cashew is threatened by a new serious destructive disease called Cashew Fusarium Wilt (CFWD), which is caused by Fusarium oxysporum. The impact of the disease has reduced income at both household and national levels. The current study was conducted to characterize CFWD and investigate chemical management options for the disease. The study was conducted during the rainy and off-rainy season(s) at Tuungane-Liwale and Kitangari-Newala in Lindi and Mtwara regions respectively. Disease characterization involved field observation of the infected cashew trees, laboratory isolation and characterization of the causative agent. Chemical management involved application of azoxystrobin, carbendazim and thiophanate methyl each at a concentration of 5, 10 and 15 g of formulated product/L. Laboratory findings revealed that the causative agent of the cashew wilting symptoms is Fusarium oxysporum characterized by whitish mycelia growth, chlamydospores, macroconidia and microconidia. The tested chemical fungicides revealed significant effects on the suppression of Fusarium wilt disease and thus enhancing cashew recovery after 120 days of application. Azoxystrobin and carbendazim reduced severity and enhanced recovery. Application of azoxystrobin (15 g/L) promoted 65.2 percent recovery of cashew from 50.0 percent of disease severity and 10 g/L of carbendazim enhanced 49.4 percent of cashew recovery from 50.0 percent severity. Thiophanate methyl exhibited no significant effect (P > 0.05) on reducing the severity of the disease, but significant effect (P ≤ 0.001) on enhancing cashew recovery whereby 15 g/L of thiophanate methyl enhanced 21.6 percent recovery from 45.0 percent severity. These findings advocate the administration of these chemicals, especially carbendazim and azoxystrobin in proper concentration for timely disease management in the affected areas. Studies to establish the effect of the applied chemicals to other biota for betterment and continued applications to combat the disease are underway.

中文翻译：

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坦桑尼亚尖孢镰刀菌引起的腰果枯萎病的特征和化学管理

腰果（Anacardium occidentale L.）是坦桑尼亚目前主要的创收作物，为超过 250 万农民带来收入。尽管腰果很重要，但腰果受到一种新的严重破坏性疾病的威胁，称为腰果枯萎病 (CFWD)，该病由尖孢镰刀菌引起。这种疾病的影响减少了家庭和国家层面的收入。目前的研究是为了表征 CFWD 并调查该疾病的化学管理方案。该研究分别在林迪和姆特瓦拉地区的 Tuungane-Liwale 和 Kitangari-Newala 的雨季和非雨季进行。疾病表征包括对受感染腰果树的现场观察、实验室分离和病原体表征。化学品管理涉及嘧菌酯的应用，多菌灵和甲基硫菌灵的浓度分别为 5、10 和 15 g 制剂/L。化验结果显示，腰果萎蔫症状的病原体是尖孢镰刀菌，其特征是白色菌丝生长、厚壁孢子、大分生孢子和小分生孢子。测试的化学杀菌剂显示出对抑制枯萎病的显着影响，从而在施用 120 天后提高腰果的恢复率。嘧菌酯和多菌灵降低了严重程度并加快了恢复。嘧菌酯（15 g/L）的应用促进了腰果从 50.0% 的严重程度恢复 65.2%，而 10 g/L 的多菌灵提高了 49.4% 的腰果从 50.0% 的严重程度恢复。甲基硫菌灵对减轻疾病的严重程度没有显着影响（P > 0.05），但在提高腰果回收率方面有显着效果 (P ≤ 0.001)，其中 15 g/L 甲基硫菌灵将回收率从 45.0% 提高了 21.6%。这些研究结果提倡使用这些化学物质，特别是适当浓度的多菌灵和嘧菌酯，以便及时控制受影响地区的疾病。正在研究确定所应用的化学品对其他生物群的影响，以改善和继续应用以对抗疾病。