Etiology and assessment of leafspot disease of sweet potato (Ipomoea batatas (L.) Lam) in selected farms in Delta State, Nigeria

Abstract

A multilocational study was conducted to investigate the associated mycoflora of leafspot disease of sweet potato (Ipomoea batatas) and evaluate the extent of leafspot damage in selected farms in the central District of Delta State. The disease assessment in four locations of study (Abraka, Sapele, Oghara and Ughelli) was based on two criteria: Number of leafspot lesions per plant and percentage area of leaf surface covered by leafspot lesions. The result indicated that leafspot lesions were greatest on the older leaves and decreased progressively to the apex. The percentage leaf area damaged followed the same trend ranging from 1-48% in various locations. The leafspot disease in Sapele was significantly (P<0.05) greater than those found in Oghara, Abraka and Ughelli. The pathogen isolation study was conducted in the laboratory in potato Dextrose Agar medium with diseased leaf specimens from the study locations. Cochlobolus lunatus, Fusarium solani, Fusarium lateritium, Non-spolulating isolate EMI-E and Mucor hiemalis, F. luteus were found associated with leafspot disease of sweet potato at percentage ferequency of 57.71, 21.71, 10.86, 6.29 and 3.43 % respectively. C. lunatus, F. solani and F. lateritium were pathogenic. C. lunatus was the most frequent and pathogenic of all the isolates. The significance of these findings has a great implication on the food security and income of resource-limited families in the central district of Delta State.

Antifungal Potentials of Aqueous Extracts of Selected Indigenous Flora Against Leaf and Stem Blight (Alternaria bataticola) Disease of Sweet Potato

“…The soil type of the area was sandy loam with organic carbon recorded at 87000 ppm, pH (water) 5. 21 The leaves were air-dried for 20 days on the laboratory bench of the Plant Protection Laboratory of the Institute, after which they were separately enveloped, oven-dried at 40 o C for 15 minutes before being separately milled into powder using Thomas Wiley milling machine (Model: ED-5, USA). The respective powders of the plant leaves were separately stored in air-tight containers, and kept in dark cupboard until required.…”

“…16 These huge losses are hinged on reductions in photosynthetic area of the affected leaves; and dissemination of toxic systemic metabolites, to slow down photosynthetic rate in areas not directly affected by the pathogen. 20,21,22 or due to clogging of water and photosyntate transport channels in vines. 23 The disease may continue as rot of roots in storage, leading to substantial maceration of tissues; and degradation of essential nutrients.…”

Pathogenicity of fungi associated with leaf spot disease of sweet potato (Ipomea batatas L. (Lam) in Makurdi, Benue State, Nigeria

“…The inocula were prepared from seven day old pure cultures of each test fungi on PDA using the method adopted from [11]. Spore suspensions were obtained by flooding the plates with 20 ml SDW and dislodging the spores with a sterile glass rod.…”

“…The production of sweet potato is constrained by the incidence of leaf spot diseases which reduces the photosynthetic area and consequently reduces yield [2,11]. Several fungi have been reported to be causal agent of sweet potato leaf spot in the rain forest zone of Nigeria and elsewhere in the world [11].…”

“…The production of sweet potato is constrained by the incidence of leaf spot diseases which reduces the photosynthetic area and consequently reduces yield [2,11]. Several fungi have been reported to be causal agent of sweet potato leaf spot in the rain forest zone of Nigeria and elsewhere in the world [11]. There is dearth of information on the fungi inciting sweet potato leaf spot in Benue State in the Southern Guinea Savannah agro-ecological zone of Nigeria.…”