Economic Losses and Economic Threshold of Cucurbit fruit fly Dacus ciliatus (Loew) and Greater Melon fruit fly Dacus frontalis (Becker) on Cucumber Cucumis staivus L. in middle of Iraq.

Abstract

     Field and laboratory studies were conducted in laboratories and fields of Faculty of Agriculture / University of Baghdad for 2011 season to estimate economic losses and economic threshold of Greater melon fruit fly Dacus frontalis (Becker) and cucurbits fruit fly Dacus ciliatus (Loew) on Cucumber Cucumis staivus L. in middle of Iraq. The results showed that the two species of flies caused an economic losses ,  and about   67.91%  of the total yields was damaged .The infection was reduced the quality and marketing value of fruits without reducing or reduction total yields.  It was found that the average weight of an infected fruit (95.15 g / fruit) does not differ significantly from the average weight of damaged fruit (94.18 g / fruit). The total yields was 5331.5 kg / dunam , and about  3637.5 kg of its was damaged .  Analysis correlation between the number of injury fruits and loss in yields showed a positive relationship  (r = 0.99654) and the equation of  expected  losses was:   Y = -6.258 + 93.318x. The results showed that the cucurbits fruit  fly  and greater melon fruit fly  was severe pests and low  percent of infected may caused high economic losses. It was found that economic threshold of these two  insect  was 1% estimated as a percent of  infected fruit and the function of the damage was: Y = -53.516 + 5351.52.