EVALUATING INSECTICIDES FOR THE CONTROL OF NARCISSUS FLIES UNDER FIELD CONDITIONS IN ISRAEL

In Israel, narcissus bulb flies (Diptera: Syrphidae) are serious pests of cultivated flower bulbs of the families Liliaceae and Amaryllidace ae. The large narcissus fly (Merodon eques) is the major pest, whereas the small narcissus fly (a new species in the genus Eumerus, yet to b e described) is only a secondary pest. The large narcissus fly is also considered a quarantine pest by the U.S.A. authorities. Narcissus bul bs, Narcissus tazetta (var. 'Ziva'), were planted in an experimental f ield at Bizzaron during November 1995 and harvested during June 1996. Currently aldicarb (Temik) is recommended for the control of narcissus fly larvae. We compared the control efficacy of imidacloprid (Confide r) and isazofos (Miral) with that of aldicarb. These letter insecticid es were applied to the soil in February, in April, or on both dates. T he mean lever of damaged bulbs in the untreated plots was 32%. Two app lications of ardicarb, one in February and one in April, reduced the d amage to the lowest lever of 0.5%. A single application of aldicarb in February, and two applications of imidacloprid - one in February and one in April - reduced the damage to 5-10%. Treatments with imidaclopr id in February or in April, reduced the damage to 12-13%. Neither one application of aldicarb in April, nor any of the treatments with isazo fos, was effective. In all treatments, larvae of the large narcissus f ly were found in only approximately one-third of the damaged bulbs. Th e level of infestation with the small narcissus fly in the untreated b ulbs was only approximately 2%. The effects of the insecticide treatme nts on the small narcissus fly were similar to those recorded for the large narcissus fly.