Abstract:
The Red Wasp Vespa orientalis and yellow wasp Polistes olivaceus are
hymenoptera insects present in our environment during spring and summer
season. Their occurrence increase dramatically during the months of July,
August and September. These wasps are found in orchards where attach grapes,
figs, date and peach. they cause severe damage on both qualities and qualities of
fruits. The adults of wasp chew on fruits causing severe injuries that may result
in bacterial and fungal infections. In order to determine the damage caused by
red and yellow wasps on grape, three grape varieties were selected: French,
Kamalie and Halawani which are the most common varieties in consumer
markets. The result of these experiments showed that the French variety was the
most damage by wasps attack and the loss of weight was 108 % gm ⁄ cluster.
The Al-Halawani was moderately elected with a loss of 71.7 gm ⁄ cluster and
Al Kamali was the least with 40.0 gm ⁄ cluster of weight loss. The average
attractiveness of wasps toward Al Halawani was 27.5 % and 72.4% for the red
and yellow wasps respectively. However the red wasp attracted largely to the Al
Kamaly variety with a 94.2 % where the yellow wasp attracted to French variety
with a 89.5%. We found that the yellow wasp has an important role in damaging
grape cluster of the all variety with a percent of 62.9% while the percent of red
wasp was 37.1%. The difference of attractiveness between red and yellow
wasps may be due to variety preference between wasps. It seems that the wasps
have large role in economic loss of grape in addition to quality effect and
lowering price of commodity.
