Assessment of Groundnut Rosette Virus Disease Transmitted by Aphid Insect-vector (Aphis craccivora Koch) as Influenced by Sowing Dates in Nigerian Southern Guinea Savannah
RICHARD, I. B
*
Department of Crop Protection, Faculty of Agriculture, P. M. B1069, University of Maiduguri, Maiduguri Borno State, Nigeria.
GONI, A
Department of Crop Protection, Faculty of Agriculture, P. M. B1069, University of Maiduguri, Maiduguri Borno State, Nigeria.
MOHAMMED, Z. H
Department of Crop Protection, Faculty of Agriculture, P. M. B1069, University of Maiduguri, Maiduguri Borno State, Nigeria.
WULGO, M. A
Department of Crop Protection, Faculty of Agriculture, P. M. B1069, University of Maiduguri, Maiduguri Borno State, Nigeria.
JOSHUA, N. B
Department of Crop Protection, Faculty of Agriculture, P. M. B1069, University of Maiduguri, Maiduguri Borno State, Nigeria.
MOHAMMED, I. K
Department of Crop Protection, Faculty of Agriculture, P. M. B1069, University of Maiduguri, Maiduguri Borno State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Groundnut rosette virus (GRD) is a major constraint to groundnut production in Sub-Saharan Africa, causing significant yield losses. The disease is transmitted by aphids and can cause up to 100% yield loss if infection occurs before flowering.
Objective: The study aimed to determine the influence of early sowing dates on the incidence and severity of groundnut rosette virus disease.
Methodology: The study was conducted at the Teaching and Research farm of the Federal University of Agriculture, Makurdi, Benue State, Nigeria, during the 2015 and 2016 cropping seasons. The 4mx 2m x 3m factorial experiment containing 24 treatment combinations (Four sowing dates- Mid-May, Late-May, Mid-June and Late-June / Two groundnut varieties- Gyadan-Mandawa and Samnut-14 / Three replications) was laid out in a randomised complete block design (RCBD) in a land area of 49m x 8m=392m2.
Results: The assessment results revealed that early sowing dates significantly influenced rosette virus disease by lowering the incidence from 20 to 30 days after sowing (DAS) in 2015 and from 20 to 40 DAS in 2016, respectively. Those plants sown early in Mid-May and Late-May exhibited lesser disease incidence compared to those sown in Mid-June and Late June from 20 to 30 DAS and from 20 to 40DAS in 2015 and 2016 cropping seasons, respectively. The influence of groundnut varieties on disease incidence was significantly different only from 20 to 30 DAS in 2016, but not from 20 to 40 DAS in 2015. Samnut-14 recorded lower disease incidence compared to Gyadan-Mandawa, which had higher disease incidence at 20 and 30 DAS, respectively, in 2016. The influence of early sowing dates on the severity of the disease was significantly different from 40 to 70 DAS in 2015 and at 40, 50 and 70 DAS in 2016 accordingly. Those plants grown early in Mid-May and Late-May recorded lesser disease severity compared to those sown in late Mid-June and Late June in the two cropping season respectively.
Conclusion: The study showed that among the groundnut varieties, Samnuut-14 recorded lower disease severity compared to Gyadan-Mandawa, which exhibited higher disease severity at 40, 60 and 70 DAS in 2015 and from 40 to 70 DAS in 2016, respectively. Therefore, an early sowing date could be strategically used for the management of groundnut rosette virus disease in this region because of its eco-friendliness and economic feasibility.
Keywords: Aphids, disease, incidence, rosette virus, severity, sowing dates, varieties