University of KwaZulu-Natal, College of Agriculture, Engineering and Science, School of Agricultural, Earth and Environmental Sciences, Scottsville 3209, Pietermaritzburg, South Africa, and The Uyole Agricultural Research Institute, Mbeya, Tanzania.
University of KwaZulu-Natal, College of Agriculture, Engineering and Science. School of Agricultural, Earth and Environmental Sciences, Scottsville 3209, Pietermaritzburg, South Africa.
Plant Dis. 2018 Jan;102(1):85-90. doi: 10.1094/PDIS-04-17-0547-RE. Epub 2017 Oct 23.
Angular leaf spot (ALS) caused by Pseudocercospora griseola is among the devastating diseases of common bean (Phaseolus vulgaris L.) in the Southern Highlands of Tanzania (SHT). This study was conducted to assess the agronomic performance and economics of yield loss associated with the disease on five bean cultivars that are widely grown by farmers. The cultivars were evaluated in a split plot design with a randomized complete block arrangement during 2012/2013 and 2013/2014. The main plots were two rates of fungicide and a control whereas the subplots consisted of cultivars. Data were collected on disease severity, yield, and yield components. Analysis of variance was done and marginal rate of returns determined using partial budget. Results indicated significant decrease in yields, number of pods, seeds, and seed weight at P < 0.05 for untreated plots. Decreases in yield were associated with ALS disease severity that in turn was influenced by cultivar and rate of fungicide used. Higher grain yield losses of as much as 61% and the lowest marginal rate of returns were recorded for unsprayed plots during heavy rains. Fungicide usage at the recommended rates should be considered during heavy rains and breeding for resistance should be taken as an economical and sustainable strategy for managing the disease.
角斑病（ALS）是由灰斑假尾孢菌引起的，是坦桑尼亚南部高地（SHT）普通菜豆（Phaseolus vulgaris L.）的毁灭性病害之一。本研究旨在评估广泛种植于农民的五个菜豆品种与该病害相关的农艺表现和产量损失的经济效益。在 2012/2013 年和 2013/2014 年期间，采用裂区设计和随机完全区组排列对品种进行评估。主区为两种杀菌剂浓度和一个对照，副区由品种组成。收集病害严重度、产量和产量构成要素的数据。进行方差分析，并使用局部预算确定边际回报率。结果表明，未经处理的地块在 P < 0.05 时，产量、豆荚数、种子数和种子重量显著下降。产量下降与 ALS 病害严重度有关，而病害严重度又受到品种和使用的杀菌剂浓度的影响。在大雨期间，未喷洒农药的地块的粮食产量损失高达 61%，边际回报率最低。在大雨期间应考虑按建议浓度使用杀菌剂，而培育抗性则应作为管理该病害的经济可持续策略。
