INFLUENCE OF STEINERNEMA-FELTIAE AND DIFLUBENZURON ON YIELD AND ECONOMICS OF THE CULTIVATED MUSHROOM AGARICUS-BISPORUS IN DUTCH MUSHROOM CULTURE

The insect pathogenic nematode Steinernema feltiae (Nematoda: Steinern ematidae) was shown to offer an alternative to the use of diflubenzuro n for the control of the mushroom fly Lycoriella auripila (Diptera: Sc iaridae). The influence of diflubenzuron and S. feltiae treatments on the yield and numbers of the mushroom, Agaricus bisporus, was studied Applications of diflubenzuron after casing significantly reduced total mushroom yields by 10-13%. The greatest yield reductions were observe d in the first flush. In the second flush, high yields were found desp ite significantly lower numbers of mushrooms. These high yields, howev er, could not compensate for the yield loss of the first flush. Some o f the treatments with S. feltiae significantly increased yields, but t hese were not associated with a particular time of application. As nem atodes did not reduce mushroom yields they were able to compete with d iflubenzuron. Although the purchase costs of nematodes were high, thei r use was more economical than that of diflubenzuron when the yield lo sses of 10% clue to casing treatments were taken into account.