Clubroot disease caused by an obligate biotroph, Plasmodiophora brassicae Woronin, causes damage to cruciferous vegetables. In the breeding of Chinese cabbage (Brassica rapa L. ssp. pekinens is) in Japan, European turnips were fbund to be a source ofclubroot-resistance (CR) genes (Yoshikawa 1981). To date, more than 50 CR Fi cultivars have been bred. However, the breakdown ofthe clubroot resist...

Botanical insecticides are increasingly attracting research attention as they offer novel modes of action that may provide effective control of pests that have already developed resistance to conventional insecticides. They potentially offer cost-effective pest control to smallholder farmers in developing countries if highly active extracts can be prepared simply from readily available plants. ...

Host race formation in phytophagous insects can be an early stage of adaptive speciation. However, the evolution of phenotypic plasticity in host use is another possible outcome. Using a reciprocal transplant experiment we tested the hypothesis of local adaptation in the aphid Brevicoryne brassicae. Aphid genotypes derived from two sympatric host plants, Brassica oleracea and B. campestris, wer...

Plants are equipped with a range of defence mechanisms against herbivorous insects. In cruciferous species, jasmonic acid, salicylic acid, and ethylene along with glucosinolates and their hydrolysis products play important roles in plant protection and plant-insect communication. In turn, a number of herbivores have adapted to plants that contain glucosinolates. As a result of adaptation to the...

Most studies on chemical and biological control of arthropod pests of agriculture do not consider the effects of partial host plant resistance. We present research using two partially resistant and a susceptible cultivar of common cabbage (Brassica oleracea var. capitata L.) and determining specific effects of interactions between the host plants, one or two common crucifer aphids (Myzus persic...

Large White Butterfly, Pieris brassicae L. (LWB) is one of the greatest pests of cruciferous cultures in Estonia, and, in the years of its biggest abundance, it can destroy a significant part of a crop. Many plants contain natural compounds that can repel and/or attract insects and protect neighbouring plants. This principle is used in a method known as companion planting. The aim of this paper...

different species of aphids in rapeseed fields of khuzestan province were identified and the dominant ones were determined during 2002-2004 field sampling. base upon the collected data, population fluctuations of rapeseed aphids vs. their natural enemies were assessed. also biology of the aphids, major species was studied under controlled conditions. the results showed that lipaphis erysimi (ka...