Pea powdery mildew caused by the obligate biotrophic fungus Erysiphe pisi DC is an air-borne disease of worldwide distribution, being particularly important in climates with warm dry days and cool nights. The disease can cause 25-50% yield losses, reducing total yield biomass, number of pods per plant, number of seeds per pod, plant height and number of nodes. The disease can also hasten crop maturity, rapidly raising tenderometer values beyond optimal green pea harvesting levels. Severe pod infectation leads to seed discolouration and downgrading of seed quality. It can also damage quality of processing pea giving tainted and bitter characteristics. Conidas and fungal debris from heavily infected crops can cause breathing and allergy problems for machinery operators.
“Crop rotation is of limited usefulness in managing powdery mildew. Powdery mildew epidemics sweep large areas with ease, and the separation of crops in time and space can delay epidemics but not prevent them.
Fungicide must be applied when the number of plants infected is still low and infection level on each plant is minimal (<5% infection).
Generally, only one application is required, unless infection comes in very early and/or conditions conducive to infection persist. In this case, follow-up applications may be required.
Extensive research throughout the agrochemical industry expanded options for powdery mildew control in the 1980s through introduction of several triazoles (sterol demethylation inhibitors) and two additional members of the morpholine group, fenpropimorph and fenpropidin. These have proven very effective in controlling pea powdery mildew.
More control options are recently available with the broad-spectrum fungicides strobirulins and anilinopyrimidines and the powdery mildew specifics spiroxamine and quinoxyfen. New mixtures are continuously being tested and approved for powdery mildew control in pea, such as the formulation mixture of the strobirulin pyraclostrobin plus the carboxamide boscalid.”
Authors: Fondevilla, S., and D. Rubiales.
Affiliation: University of Cordoba, Spain.
Title: Powdery mildew control in pea. A review.
Source: Agron. Sustain. Dev. 2012. 32:401-409.