LABORATORY AND FIELD STUDIES TO DETERMINE THE EFFECT OF A BIOCIDE (DELFIN) AND AN INSECT GROWTH REGULATOR (CONSULT) ON THE PINK BORER SESAMIA CRETICA LED. AND CERTAIN NATURAL ENEMIES IN MAIZE FIELDS IN EGYPT.

Document Type : Original Article

Authors

1 Plant Protection Department, Faculty of Agriculture, Moshtohor, Zagazig University, Egypt

2 Plant Protection Research Institute, Agricultural Research Centre, Dokki, Giza, Egypt

Abstract

The efficacy of Delfin (a commercial product of Bacillus thurin­giensis and Consult (an insect growth regulator) on the 1st instar larvae of Sesamla cretica was studied. The LC50 value after 48 hours from Del-fin treatment was 5.2 x 104 S.U. this value was 72 p.p.m., 24 hours af­ter treatment of Consult. A negative relationship was found between the applied concentration of Delfin, Consult and LT50 values where it short­ened by increase of applied concentrations. A program was followed in the field on (16 experimental plots) of early maize cultivation of 1998 and 1999 maize season that received 3 treatments and control of 4 rep­licates each. The treatments were Delfin + 1% NaCI, Delfin (0 525 kg / feddan) and Consult (200 mt / fedden). All treatments were applied 20 days after sowing. Such treatments induced % reductions in the num­bers of perforated leaves due to S. cretica larval feeding by 66.51, 64.74 and 42.59 % In 1998 and by 38.84, 26.85 and 28.51 % in 1999 for the three treatments, respectively. In addition reduced the mean lar­val counts /10 infested plants and caused % reduction than control by 47.39, 40.62 and 21.88 % in 1998 and by 27.01, 20.11 and 13.79 % in 1999 for the three treatments, respectively. Spraying maize by Delfin or Delfin + 1% NaCI had no effect on parasitization of Platytelenomus hy­las (an egg parasitoid) or on Apanteles sp., Bracon breyicornis and Mete­orus rubens (three larval parasitoids). Consult treatment caused signifi­cant reduction in the percentages of parasitism by P. hylas and also no parasitized S. cretica larvae was detected in this treatment.