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| Epidemiology And Occurrence Of Groundnut Ringspot Virus (Grsv) Infecting Groundnuts In Western Kenya |
L W Murere, B Mukoye, H K Were and M Kollenberg
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Abstract:
Groundnuts (Arachis hypogea) is an annual oilseed legume crop grown by small holder farmers in Kenya for its economic and nutritive value. However, its yields have declined upto 680 kg ha-1 than its genetic potential of 1690 kg ha-1 attributed to abiotic and biotic factors. Biotic factors are of economic importance which include Pests and diseases. Viruses are among biotic factors for yield reduction globally. These include; Tomato spotted wilt virus (TSWV) Groundnut bud necrosis virus (GBNV) among others. Groundnut ringspot virus (GRSV) has been reported in South Africa, Ghana, Brazil, USA and Argentina infecting groundnuts, tomatoes, watermelon, soy beans, peppers among others. GRSV and TSWV have similar biological symptoms thus can only be distinguished either serologically or by molecular tests. GRSV Symptoms have been noted on groundnuts and other hosts in Kenya but no documented report on its epidemiology, prevalence and distribution of GRSV in Kenya. The objective of the study was to determine prevalence and distribution of GRSV on groundnuts in western Kenya. Diagnostic survey was conducted in all agro ecological zones of western Kenya (LM1, LM2, LM3 and UM1) during short and long rain seasons. Disease incidence and severity observed, recorded and samples taken for serological and molecular tests. Leaf samples collected for serological analysis used polyclonal antisera against GRSV and TSW. GRSV occurs in surveyed regions with variant incidence; Chwele having the highest incidence (45.04 %) followed by Kimilili with incidence of 39.95 %. In some regions GRSV and TSWV co-infected groundnuts displaying same symptoms. Kapkateny region had the lowest incidence (17.75 %) with significant difference of (0.05). The study showed that GRSV occurs in surveyed counties of western Kenya with variant incidence and severity which is the first report in Kenya and third country in Africa to report on occurrence of GRSV which is a big concern. Introgression of resistant genes into local groundnut varieties to gain resistance to the virus be done with urgency. Additionally, farmers be advised to adopt integrated pest management to minimize thrips from transmitting virus from primary host.
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