Integrated disease management of powdery mildew (Leveillula taurica(Lev.) Arn.) of Chilli (Capsicum annuumL.)

Abstract

Integrated disease management of powdery mildew (Leveillula taurica (Lev.) Arn.) of Chilli (Capsicum annuum L.) Abstract Chilli (Capsicum annuum L.) powdery mildew incited by Leveillula taurica (Lev.) Arn. (¼ Oidiopsis taurica (Lev.) Salmon.) is one of the most serious diseases in Tamil Nadu. The leaf extracts of Azadirachta indica A. Juss. (10%) and bulb extracts of Allium sativum L. and A. cepa L. (5%) were highly effective in inhibiting conidial germination of L. taurica under greenhouse and field conditions. Among the antagonistic microorganism screened, maximum reduction in conidial germination was recorded by the culture filtrates of T. viride Per. ex. S. F. Gray., T. harzianum Rifai. and P. fluorescens Migula. under greenhouse and field conditions. Spraying of dipotassium hydrogen orthophosphate and monopotassium phosphate were highly effective in reducing chilli powdery mildew under greenhouse and field conditions. Among the chemicals tested, dipotassium hydrogen orthophosphate significantly increased the protein, total phenol, phenylalanine ammonia lyase, polyphenol oxidase and peroxidase activity of the leaves. In an integrated disease management, foliar spraying with sulphur alternating with dipotassium hydrogen orthophosphate or plant extract Azadirachta indica was as effective as alternating with wettable sulphur fungicide.

Detached Leaf Test for Evaluation of Resistance to Powdery Mildew in Pepper

“…Infected leaf areas of 40% were observed for AcII and BcII at 25 days after inoculation (Figure 3). Disease evaluations on pepper plants were realized at 21-50 days after inoculation by spraying conidia [3,7,9,11,[13][14][15][16] and at flowering time after inoculation by placing infected plants near to healthy plants [17][18][19][20][21][22] under greenhouse conditions During these evaluations the genotypes, which had infected leaf areas of 40.1 -51% or more, were accepted as highly susceptible [7,[18][19][20][21].…”

“…Assessments of powdery mildew resistance are performed on whole potted plants in a greenhouse. The abaxial surface of healthy plants with 45-60 days growth are inoculated by pressing gently sporulated areas of old infected leaves [6][7], by transferring the spores with a small brush [7][8][9]), and by spraying a conidia suspension (10 4 -10 6 conidia/ml) in sterile distilled water or tap water [3,5,7,[10][11][12][13][14][15][16]. In some studies, inoculation of plants was carried out by placing infected plants in the vicinity of healthy plants [17][18][19][20][21][22].…”

“…The plants were maintained at 16 °C for 24h in dark, then at 22 °C for 14h light and at 16 °C for 10h dark (3) or at day temperature (21 °C, 25 °C) and night temperature (19 °C, 22 °C) after inoculation [5,9,[14][15]. Some authors kept pepper plants for 24h in plastic cages after inoculation [5,13,[15][16]. Tests for resistance of pepper genotypes to powdery mildew throughout a breeding program under greenhouse conditions need high amounts of inoculum, labour, time and large experimental area.…”

Novel sources of resistance to powdery mildew (Leveillula taurica (Lév.) Arnaud) in pepper

“…However, the production of photoassimilates is dramatically decreased during a period of time which can be 10 limiting for plant development and fruit setting. If defoliation takes place during the fruiting time, fruits can be exposed to excessive irradiation, increasing the risk of sunscald (Elad et al, 2007;Sudha and Lakshmanan, 2009). Therefore, leaf shedding is considered as an indicator of susceptibility.…”

Molecular Mapping of PMR1, a Novel Locus Conferring Resistance to Powdery Mildew in Pepper (Capsicum annuum)

“…Leveillula taurica , an obligate fungal plant pathogen belonging to the ascomycetes, causes powdery mildew in various vegetable crops, resulting in significant quality and yield losses. In the past few decades, the incidence of L. taurica powdery mildew has been increasing in both greenhouse- and open field-grown peppers worldwide (Damicone, 2009 ; Sudha and Lakshmanan, 2009 ; Cerkauskas et al, 2011 ). Premature defoliation caused by powdery mildew severely reduces crop yields and makes fruits unfavorable for marketing.…”