Occurrence of aphid vector and genetic tolerance to infection by potyvirus in hot pepper

Abstract

The productivity and marketable quality of hot pepper (Capsicum annuum var. annuum L.) are low in tropical regions mainly due to virus infections and lack of effective virus management strategies. The absence of effective virus management strategies could be attributed to lack of information on virus vectors and host resistance. Parental (P 1 and P 2 ) and progeny (F 1 , B 1 , B 2 and F 2 ) generations of five hot pepper crosses were grown in Ethiopia at three sites (Bako, Hawasa and Melkasa) to monitor number and species of potential aphid vectors, disease incidence levels with regards to natural infections by Potato virus Y (PVY) and Ethiopian pepper mottle virus (EPMV) complex, and to determine genetic tolerance of the crop to the viruses. Disease incidence was assessed before the flowering stage of the crop plants using visible disease symptoms due to infections by PVY and EPMV. The serological tests revealed presence of symptomless genotypes of the crop to the virus infections. Aphid species potentially transmitting the viruses, such as Acyrthosiphon pisum (Harris), Aphis fabae (Scopoli), and Myzus persicae (Sulzer), were identified from specimens caught by yellow water traps. The highest number of aphids from yellow water traps was recorded at a dense foliage growth stage of the crop at Melkasa. Highly significant variation was observed among generations of the five crosses in response to infections by PVY and EPMV complex. The most susceptible parents had the levels of disease incidences ranging from 80 to 90%, whereas their progenies had only below 30% incidence levels. The most tolerant parent remained symptomless to the natural infections of PVY-and EPMV-complex. Incidence levels in progenies of a cross from the most susceptible and tolerant parents remained below 20%. Based on serological test, the proportion of PVY-positive plants ranged from 0 to 75% and of EPMV-positive plants from 0 to 25%, with 0 to 17% co-infection by the two viruses. Availability of virus sources in the vicinity, efficiency of aphids in vectoring, weather conditions during the growth period, genetic tolerance and the growth stage of the crop affected natural infection by PVY-and EPMV-complex. Exploitation of the genetic potential of introduced elite genotypes and their progenies along with breeding elite local cultivars for resistance Electronic supplementary material The online version of this article (and excluding aphid vectors at young (seedling) stage of the crop plants could be helpful for minimizing losses in yield and quality of hot pepper due to infections by PVY-and EPMV-complex.

Effect of Netting Duration on Ethiopian Pepper Mottle Virus (EPMV) Infection and Aphid Infestation of Hot Pepper (Capsicum annuum L.) in Central Rift Valley Region of Ethiopia

“…Starting 20 days after transplanting, all pepper plants in each plot were visually assessed for the incidence of EPMV infection caused by natural infestation special aphid's infestation. Well established symptoms based evaluation method for EPMV was used for rating of the incidences [8,15]. Ethiopia pepper mottle virus incidence on each experimental treatment was recorded by counting number of diseased plants and calculating as the proportion of the diseased plant over the total number of stand count per treatment.…”

Colonization of the Biomass Energy Crop Miscanthus by the Three Aphid Species, <I>Aphis fabae</I>, <I>Myzus persicae</I>, and <I>Rhopalosiphum padi</I>

“…In Picardie, a region located in the northern part of France, a Þeld survey of miscanthus crops was conducted in 2011 (29 AprilÐ29 July). Yellow water traps were placed on a pole at a height of 50 cm above the canopy and 50 m from the border to attract and collect insects ßying over the Þelds (according to the protocol detailed in Marame et al 2010). Collected data showed that all the common aphid species occurring throughout northern France on many crop plants were present.…”