الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
Field experiments were carried out during two successive summer seasons of 2011 and 2012 at the Experimental Farm, Abees, Agricultural Research Station, Faculty of Agriculture (Saba-Basha), Alexandria University to evaluate the efficiency of certain treatments on the sucking pests attacking cucurbit plants.
One variety of squash (El-Askandarani) and one variety of cantaloupe (Melon ananas Hy F1 PMR) were used during the course of this study. The evaluated treatments were thiamethoxam, azadirachtin, abamectin, salicylic acid and aluminum foil.
The infestations of the main insect pests (aphids, whiteflies, thrips, jassid) attacking squash and cantaloupe plants were inspected under the field conditions during 2011and 2012 seasons.
The efficacy of the evaluated treatments for controlling the transmitting insects (whiteflies and aphids) of virus diseases and the virus transmission in certain cucurbitaceous crops (squash and cantaloupe) were determined.
Moreover, Plant samples of squash with mosaic symptoms suspected of being infected with zucchini yellow mosaic virus (ZYMV) were collected from naturally infected plants, grown at the experimental farm. Laboratory experiments through serological test by indirect ELISA were used for identifying the transmitted virus in the season of 2012. Seven species of aphids were tested for the ability to transmit ZYMV from infected to healthy squash plants. The obtained results can be summarized as follows:
1. Effect of ZYMV on certain yield parameters:
Symptoms of ZYMV infection appeared after 7 days post inoculation and initially consisted of abrupt reduction in flower production followed by vein clearing of the least mature leaves. Subsequent foliar symptoms included systemic mosaic, enations, and deep serration.
Zucchini yellow mosaic virus (ZYMV) infection reduced several yield parameters, plants inoculated at cotyledon stage showed 51.4% reduction and 29% in seven-leaf stage in number of fruits per plant. Yield losses were 64.5 % and 41.5 % in plants inoculated at Cotyledon and seven leaf stages, respectively.
2. Survey of insects/pests infesting squash and cantaloupe plants
No insecticides were applied during that season to have accurate figures on the population densities of those insect-pests. The main detected insect pests infesting squash plants were aphids, whiteflies, thrips and jassid. Three pests (whitefly, thrips and spider mite) were detected attacking cantaloupe plants.
2.1. Squash plants
2.1.1. Season 2011
It is found that there was a positive correlation between all inspected individual insect-pests (except thrips) and both of temperature and the prevailing relative humidity (R.H.) during the cultivation summer season of 2011.
The highest inspected number of Bemisia tabaci was found during the first week of July (119 individuals / 30 leaves).On the other hand, the aphid number was very high during the first week of June (105 insects/30 leaves).The counted number of thrips was 1176 insects/30 leaves during the last week of May. The highest number of jassid was found in the first of June (15 insects/30 leaves).
2.1.2. Season 2012
The number of the white fly Bemisia tabaci appeared in the third week of May (22 insect/30 leaves). The highest number was found during in the third week of June (38 insect/30 leaves). The aphid population was very high during the third week of May (252 insects/30 leaves.
The highest recorded number of thrips was 3483 insects/30 leaves in the second week of May. However, the inspected jassid number was relatively low, the peak of population took place during the third week of May (28 insects/30 leaves).
There was a slight positive correlation between the temperature during the cultivation summer season of 2012 and the number of individuals of the whitefly, aphid, thrips and jassid. Meanwhile, there was a lower negative correlation between the prevailing relative humidity (R.H.) and both of aphid and thrips.
2.2. Cantaloupe plants:
2.2.1. Season 2011
Three pests were detecting attacking cantaloupe plants. The highest number of whitefly was found during the first week of July (1035 insect/30 leaves).Plants were infested with the first thrips attack shortly after germination, the highest number was found during the last week of June (30insect/30 leaves). The number of the spider mite increased at the end of season and as the humidity decreased.
2.2.2. Season 2012
The highest number of whitefly was found during in the last week of June (368 insects/30 leaves).The highest number of thrips was found in the first week of June (219 insects/30 leaves). The highest recorded number (757 and 571 mite/30 leaves) of the spider mite detected at the 7th and 14th of July, respectively.
In general, the only negative correlation coefficient was observed between both temperature & relative humidity and the inspected number rate of thrips on squash and cantaloupe plants in both seasons.
3. Efficacy of the tested treatments against both of aphid and whitefly
3.1. Season 2011:
3.1.1. Squash plants.
3.1.1.1. Aphids.
Most of the evaluated treatments found to be effective with significant differences on aphid. The superior treatment of initial reduction against aphid was thiamethoxam giving 100% followed by aluminum foil, abamectin, salicylic acid and azadirachtin that gave 73, 72.2, 66 and 41 %, respectively.
Concerning the general mean of the residual reduction percentage throughout the whole inspection periods, thiamethoxam was the most effective treatment giving (98.9%) followed by salicylic acid (63.9%), azadirachtin (54.7 %), abamectin (21%), and aluminum foil (16.7%).
3.1.1.2. Whitefly
3.1.1.2.1. Adult stage
Most of the evaluated treatments found to be effective on whitefly adult (Bemisia tabaci). Regarding the initial reduction percentage, aluminum foil, azadirachtin and salicylic acid were the most effective treatment giving (100%) followed by abamectin (100% and 93.7%) and thiamethoxam (90.5% and 89.7%) in the absence and presence of weeds, respectively.
According to the calculated general mean of residual reduction percentage throughout the whole inspection periods, the superior effective treatment was aluminum foil (91% and 90.07%) followed by salicylic acid (65.6% and 59.28%), azadirachtin (64.4% and 52.5%), thiamethoxam (62.6% and 49.5%) and abamectin was the least effective treatment giving (38.47% and 6.7%) in the absence and presence of weeds, respectively.
Also, it is obvious that aluminum foil treatment almost showed a steady effect in reducing the number of whitefly adults in all inspection periods from the beginning of treatment up to 10 days post-treatment.
3.1.1.2.2. Immature stage
The data clearly showed that the number of individual immature stage highly decreased on squash plants in the presence of weeds between plants. The evaluated treatments induced different initial reduction percentages after two days post treatment. The superior treatments were thiamethoxam and azadirachtin which gave (80.7% and 22%) and (80% and 43%), in the absence and presence of weeds, respectively, followed by salicylic acid (35% and 8.8%) aluminum foil (33% and -25%) and the least one was abamectin which gave (14% and -67.6%) initial reduction.
Azadirachtin achieved the highest general reduction mean estimated by 85.8% followed by thiamethoxam (74.03%), aluminum foil giving (64%), salicylic acid (58.2%) and abamectin (35.3%) in the absence of weeds.
However, all the treatments seemed to be ineffective along each of the inspection periods with the presence of weeds showing the importance of weed control even in the control of certain insect pests as whitefly. Moreover, all the tested treatments were more effective on the adult more than the immature stage especially the treatment of aluminum foil.
3.1.2. Cantaloupe plants:
3.1.2.1. Whitefly
3.1.2.1.1. Adult stage
3.1.2.1.1.1. The 1st treatment application
The results indicated that salicylic acid was the most effective among the tested ones against the adult stage of whitefly (Bemisia tabaci) populations on cantaloupe plants inducing initial reduction of 83.9% and 73.9% followed by aluminum foil giving