RESUMEN
Epidemic of Cashew Fusarium wilt disease (CFWD) has been a continuous focal challenge in the cashew farming, in Tanzania. Limited to edaphic conditions as a major factor in its epidemic, the current study aimed to assess the habitat-disease relationship. Purposive surveys involving assessment of disease prevalence and habitat compositions were conducted across four landscapes of southeastern zone from 2019 to 2023. Findings revealed a widespread of CFWD across diversified landscapes possessing varying habitat characteristics, mainly cultivated land with mature cashew, brownish sand loamy soils, grassland or shrub vegetation, seasonal river streamlines and natural water wells. The highest disease incidence and severity were noted at Nachingwea/Masasi plain (99.28:88.34%) followed by Liwale inland plain (98.64:89.3%), Coastal zone (72.72:59.83%) and Tunduru dissected plain (62.13:54.54%). The habitat characteristics were strongly similar within the landscape (0.86-Jaccard index) except between villages of the coastal zone (0.71-Jaccard index). Across landscapes, Nachingwea/Masasi plains and the Coastal zone were strongly similar to Tunduru dissected plain (0.63-1.0-Jaccard index), but strongly dissimilar with the Liwale inland plain (0.67-0.70- Jaccard distance). Furthermore, the presence of greater than 0.5 suitability indices across landscapes were revealed, with Liwale inland plain having strongest suitability index of 0.743 followed by Coastal zone (0.681), Tunduru dissected plain (0.617) and Nachingwea/Masasi plain. Significantly, the habitats had an increase of 0.1 suitability index, and positively correlated with disease prevalence by triggering disease incidence of 13.9% and severity of 31.4%. The study for the first time revealed the presence of an association between disease prevalence and landscape habitat characteristics of southeastern, Tanzania; paving the way to inclusive thinking of habitat as one of the drivers in the prevalence of fusarium wilt disease of cashews. Further research on the genetic coevolution of Fusarium oxysporum across landscapes to strengthen disease risk management in the cashew industry is recommended.
Asunto(s)
Anacardium , Ecosistema , Fusarium , Enfermedades de las Plantas , Tanzanía/epidemiología , Anacardium/microbiología , Fusarium/aislamiento & purificación , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/estadística & datos numéricos , Productos Agrícolas/microbiología , PrevalenciaRESUMEN
Weeds are among the limiting factors that influence low production of economically important crops including cashew (Anacardium occidental L.). Shrub weeds attribute to inter-competition for resources, hinder harvesting and ultimately reduce cashew yields in Tanzania. The current study determined the distribution, characteristics and chemical control option of Dichapetalum Engl in Lindi and Mtwara regions, Southeastern Tanzania. The distribution study involved a survey for weed presence along the areas of Lindi and Mtwara regions. The characterization included distilling, and assessing the growth and development properties of shrub weed. Chemical herbicides; glyphosate 480g. ai/l, 2, 4 D - Dichlorirophenoxyacetic 720g. ai/l, triclopyr 160g a.i./l and 1:1 mixture of glyphosate 480g a.i./l plus triclopyr 160g a.i./L at 15, 20 and 25 mls of formulated product/L of water per 4 m2 were tested on tender, mature and blooming growth stages of D. Stuhlmannii and three spraying frequencies. Findings revealed that the D.stuhlmannii, is a widely distributed shrub weed in Lindi and Mtwara regions. The weed was characterized with three main growth stages of seedling, mature and blooming with a long tap root and evergreen throughout the wet and dry seasons. The tested herbicides revealed the potential suppression of D. Stuhlmannii growth. Glyphosate and a mixture of glyphosate + triclopyr at 15 ml/L outperformed triclopyr and 2, 4 D across all the growth stages. Double spraying of glyphosate and its mixture bettered frequencies of triclopyr and 2, 4 D. The delayed regrowth of suppressed shrub weed took 90-120 days after application of herbicides. The current study recommends for single or double applications of glyphosate herbicides at 15 ml/L or 10,700 ml/ha on tender or mature D. Stuhlmannii in cashew farms. Further studies on the economic feasibility and effect on the microbiota of applied fungicides are required.
RESUMEN
Background: Weeds are important biotic agents that have a big impact on plant yields and growth. In southern Tanzania, the timing and effects of weeding were studied in relation to cashew flushing and flowering. Methods: For the study, three cashew development centers (CDC) were chosen. Herbicides, manual hoeing (tillage), slashing, and scratching were the four weeding methods allocated. Two clones (AC4 and AZA17) of cashew trees that were 10 years old were treated. Phase 1 (after harvest), Phase 2 (during the rainy season), and Phase 3 (before to flushing of the cashew flowers) are the three distinct weeding phases. Results: Compared to other approaches, hand hoeing (field tillage) significantly (p < 0.05) influenced early cashew flushing and blooming. Slashing was least effective, followed by hand hoeing and the application of herbicides. Phase 1 had a substantial (p < 0.05) impact on the flushing of cashews and Phases 1 and 2 had the greatest (p < 0.05) and least (p < 0.01) effects on cashew flushing and blooming, respectively. Both the weeding techniques and the weeding time had no effect on the cashew clones (p > 0.05). Compared to other techniques, hand hoeing required a lot of time. Conclusion: It is often advised to weed through soil opening during wet seasons because it improves and hastens the occurrence of the factors that determine cashew yields (flushing and blooming). However, additional research is advised on the role that timely weeding and weeding techniques have in improving cashew yields along different cashew tree ages in southern Tanzania.