EFFECT OF USING AGRYL, SILVER MULCH, NON INSECTICIDES AND INSECTICIDES AS A METHODS OF EXCLUDING WHITEFLY AND SILVER LEAF DISORDER AFFECTING FALL GROWN SQUASH (Cucurbia pepo, L.)

The study was carried out during the two successive fall seasons. 1999 and
2000 at Nubaria. A squash hybrid Ambassador was cultivated under the drip irrigation
system. Nine treatments were usee as follows: Agryl17. Silver mulch. Azadrachtin.
mineral oil. Admire. Silver mulch + Azadrachtin. Silver mulch + mineral oil . Silver
mulch + Admire and control (without treatments). The aim of the study is to investigate
a reliable strategy using non inseclicidal treatments for reducing the incidence of
Silver leaf disorder that affect yield and Quality. The obtained results could be
summarized as follows:-

Protected treatments affected the incidence of whitefly infeslation. but
decreased significantly the occurrence of whitefly than that of control. Agryl
provided comptete prevention of whitefly during the two seasons. Silver mulch
treatment showed a high mean counted numbers of whitefly after 33 days from
planting. Spraying treatment of both Azodrachtin and mineral oil were
significantly reduced the Incidence of whitefly than the treatments Silver mulch
and control. Combined treatments of each Silver mulch with Admire and
Azadrachtin and mineral oil were insignificantly the efficient ones that greatly
reduced the number of whitefly.
No symptoms of squash silver leaf had been detected on plants covered with
Agryl. The percentage of infeclion reached 100% on the control plants after 45
days. The combined treatments of Silver mulch + Admire reduced the
percentage of infection followed by Silver mulch + Azadrachtin. respectively.
As for total yield. Agryl17 gave the highest significant total yield followed by the
combined treatments of Sitver mulch + Azadrachtin and Silver mulch + Admire.
respectively. The control treatment showed significantly the lowest total yield.
A positive correlation between the number of whitefly and percentage of
infection with correlation coefficient 0.827. On the other hand. a negative
correlation was observed between totat yield and number of whitefly with
correlation coefficient -0.720.