Major Diseases of Groundnut (Arachis hypogaea L.) in Benue State of Nigeria

Aim: Groundnut (Arachis hypogaea L.) farming is an important source of income, food and employment to the teaming population of Benue state indigenes. The disease is one of the major biotic factors undermining groundnut production in the area particularly when the crop is grown in rotation after cultivation.

Methods: Field survey of 2011 and 2012 was conducted to assess the incidence and severity of major diseases of groundnut in Obi, Gboko, Guma and Makurdi Local Government Areas of Benue State. Three villages (groundnut fields) were investigated from each location. Quadrat measuring 1 x 0.5 m was thrown at random in different parts of the farm for the disease assessment.

Results and Conclusion: In 2011 and 2012 surveys, symptoms of Cercospora leaf spot, rust (Fungal infection) and rosette (Viral infection) were observed with variation in their percent incidences and severities in the three villages investigated from the four agro-ecological locations. Results showed that there were significant differences (P<0.05) in the leaf spot incidence in 2011 rosette incidence in 2012 among the agro-ecological locations. The highest leaf spot incidence of 43.34% was recorded at Obi agro-ecological location in 2011 and while Gboko agro-ecological location recorded higher disease incidence of 45.36% followed by Guma location in 2012. Makurdi Agro-ecological location recorded the lowest leaf spot incidence in both 2011 and 2012. The highest rosette incidence of 28.07% was recorded at Makurdi location compared to other agro-ecological locations in 2012. The severity of leaf spot disease in both 2011 and 2012, and rust in 2011 were not significantly different (P>0.05) among the four locations. The severity of rust and the severity of rosette in both 2011 and 2012 were significantly (P<0.05) different among the locations. In 2011, higher rosette severity of 40.07% was recorded at Makurdi location compared to Obi, Guma and Gboko agro-ecological locations. In 2012, Obi location recorded significantly the highest rosette severity of 53.2% followed by Guma and Makurdi agro-ecological locations and while Gboko location recorded 35.1% as the lowest rosette disease severity. Similarly, in 2012 the result showed that Guma and Gboko locations recorded higher rust disease severity of 70.1% and 62.3%, respectively compared to Makurdi and Obi agro-ecological locations. Results of the interaction with the famers through participatory rural appraisal (PRA) using Pair Wise Ranking method revealed seven major production constraints that undermined groundnut cultivation in the areas of which lack of finance ranked the most important production constraint (43.0) while weed (37.75), disease/insects problems (35.25) and inaccessible to chemicals were highly important problems resulting to unattainable yield in groundnut production in this agro-ecology. The result of this study will serve as a first-hand information to the farmers in order to adopt effective disease management strategic option to curtail menace of the diseases and also help the government in formulating favorable agricultural policy that will enhance production in the State.