Exploring the impact of non-chemical methods on the control of bulb mite (Rhizoglyphus robini Claparáde) and yield of saffron (Crocus sativus L.)

Abstract

The bulb mite (Rhizoglyphus robini) causes damage to a number of crop and ornamental plant species, including saffron (Crocus sativus). A split-plot experiment based on a randomised complete-block design was conducted between 2011 and 2015 to investigate the effects of solarisation using transparent plastic along with planting date and first irrigation on the population of bulb mite, yield of saffron, size of corms produced and extent of corm infection. Solarisation significantly decreased the mite population and increased the saffron yield (P<0.01). Increased yields were achieved by planting in June rather than in September. However, the use of irrigation immediately after planting in June increased the mite population and decreased saffron yields. A combination of solarisation in the first year and planting in June of the next year with no irrigation after planting resulted in a reduction of 94% in the population of the mites and a 3.48-fold increase in saffron yield. In Iran, saffron corms should be planted in June but not irrigated until September. If planting does occur in September then irrigation should be applied immediately after planting.