ISHS Acta Horticulturae 82: Symposium on Production of Protected Crops in Peat and other Media
APHID CONTROL ON TOMATOES IN A HYDROPONIC SYSTEM |
| Authors: | R. Dunne, M. Donovan |
| Abstract:
While aphids seldom present a problem in normal tomato growing where routine applications of insecticides are made for control of whitefly and other pests, infestations frequently reach damaging levels in crops where biological control of whitefly and red spider mite is practised. In such situations, since it is undesirable to apply an aphicidal spray or fumigation due to deleterious effects on the natural enemies, the common recommendation is to apply the insecticide as a root drench or spot treatment. This drench is expensive and extremely laborious to apply due to high use of water needed while the spot treatment is troublesome and may have to be repeated. The main aphid species found on tomatoes in Ireland is Macrosiphum enphorbiae (Thomes) both green and red forms of which occur. Myzus persicae (Sulz) also occurs but to a lesser extent, while Aulocorthum solani (Kalt) is sometimes found on young plants. Parasitism of M. persicae by naturally occurring parasites is usually sufficient to maintain populations below economic injury levels but M. solanifolii does not appear to be attacked by parasites to the same extent. It is, however, often attacked by entomophagous fungi but these generally do not effect control until considerable damage occurs. Preliminary investigations on aphid control by the addition of a aphicide to the nutrient solution in a hydroponic system have been made at Kinsealy. Price (1975) suggested that the addition of pesticides to a hydroponic system at much lower concentrations than in normal spray application methods will give effective pest control. Morgan (personal communication) found that adding benomyl to the nutrient solution at 1/5 of the normal spray concentration caused phytotoxicity in tomatoes. The lowest concentration used in this work was 1/5 of the normal spray concentration for pirimicarb which is 5 g product per 10 1 water. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
