Effect of sowing date and straw mulch on virus incidence and aphid infestation in organically grown faba beans (Vicia faba)

Abstract

The effect of sowing date on aphid infestation and the incidence of aphid-transmitted viruses were investigated in organically managed, small-scale field experiments with two faba bean cultivars over 3 years . As an additional factor, straw mulch was applied in 2 of the 3 years shortly before the start of vector activity in May. Virus incidence was determined using enzyme-linked immunosorbent assay and immunoelectron microscopy. Aphid flight activity was monitored using standard yellow water traps. Bean colonising aphids were assessed throughout the vegetation period by counting the number of plants infested with Acyrthosiphon pisum, Megoura viciae and Aphis fabae. Pea enation mosaic virus and bean yellow mosaic virus were the most abundant aphid-transmitted viruses, being detected in 22-54% and 9-69%, respectively, of the total number of virus-infected plants analysed per year. Further aphid-transmitted viruses found in faba bean were bean leaf roll virus, beet western yellows virus, clover yellow vein virus (in 2002) and soybean dwarf virus (in 2004). A. pisum was the predominant aphid species colonising faba bean plants. Early sowing compared with late sowing led to a significant reduction of the total virus incidence in faba bean in all 3 years. However, significantly decreased levels of A. pisum colonisation as a result of early sowing were observed only in 1 year and one cultivar. Irrespective of sowing date, straw mulching had no significant effects on virus incidence and aphid colonisation. Compared with late sowing, early sowing significantly increased bean yield in all 3 years and kernel weight in 2 years, whereas straw mulching had no effect on yield.

Effects of mulching materials on agronomic characteristics, pests of pepper (Capsicum annuum L.) and their natural enemies population

“…In this study A. gossypii first appeared at the seedling stage, sucking the plant sap, leaving the leaves curled and wrinkled which were mostly observed on the control plots with similar finding made by Brust (2008). Results from this study and studies by Saucke et al (2009) have indicated that mulches have no significant effect on aphid colonisation. This may be due to fact that straw and other mulching materials used in this study probably do not exhibit pest-repellent properties.…”

Grain Legumes

“…For example, it is recommended to sow early so the plants are well developed before aphids start to colonise the crop. However, in a study on faba beans in Germany, aphid infestation was not consistently reduced through early sowing; nevertheless early sowing resulted in lower virus incidence, possibly because of stronger mature plant resistance in the early-than in the late-sown beans (Saucke et al 2009). While grain legumes grown to maturity are typically sown in the spring or autumn, summer sowing is possible if they are used as cover crops.…”

Suitability of NDVI index to pea condition evaluation at diverse phosphorus fertilization

“…The effects of feeding by A. pisum is the reduction of yield resulting from sap sucking. The pest can also contribute to the spread of viral diseases (Saucke et al, 2009). NDVI index so far was used to asses both infestation of plants by aphids and the impact of nutrient deficiencies on the condition of plants, however, these factors were analyzed separately.…”