الفهرس 
Introduction
Distribution of the tomato leafminerOnly 14 pages are availabe for public view
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Abstract
Tomato, Lycopersicon hirsutum L. is a crop of outstanding importance in Egypt on account of its great value for local consumption.
The present investigations were conducted at the Experimental Farm of Plant Protection Department, Faculty of Agriculture, Assiut University throught the period extended from 2012 to 2014.
The specific purposes of this research were as follows:
1- Studying population trend of T. absoluta under environmental field conditions of Assiut.
2- Studying factors affecting the infestation of tomato by the pest.
3- Studying vertical distribution of the tomato leafminer on tomato plants under field condition.
4- Studying relative susceptibility of four commercial hybrids of tomato to leafminer infestation.
5- To evaluate the effectiveness of some pesticides against the tomato leafminer under field conditions.
The obtained results could be summarized as follows:
1- Brief description of the tomato leafminer, Tuta absoluta
The tomato leafminer, T. absoluta is a nocturnal micro-Lepidopteran insect of the Gelechiidae family. It has four life stages: egg, larva, pupa, and adult. Larvae create irregular mines that are about half the width of a pencil line. The mining occurs between the upper and lower leaf surfaces, resulting in clear patches that are often partially filled with larval waste. As each larva develops in its mine, the mine becomes wider and may show some finger-shaped protrusions along the edges.
2-Population studies of the tomato leafminer infesting tomato plants
2.1- Winter plantation
The infestation of tomato by the leafminer started early in the first week of November (5.48 larvae / 10 leaves). The number of larvae increased gradually until reaching its maximum level around the end of November and the beginning of December. Then, the population was declined until the end of January. As for the predator, the population was appeared on tomato plants during the period extended from the first week of November up to the third week of January.
2.2-Summer plantation
The infestation of tomato during summer plantation occurred after 39 days from tomato transplanting nearly during the first half of April. The population then increased to tend to establish on tomato plants during the middle of April. Maximum infestation occurred after 74 days. Thus, the peak of abundance could be attained during the first week of May (46.50 individuals / 10 leaves). After the population reached its highest level (peak), it generally declined and reached the minimum population level after 130 days (toward the first week of Jul.).
from the above mentioned results it could be concluded that the numbers of the tomato leafminer were significantly higher in summer plantations than that of winter plantations. The differences in levels of infestation between the two plantations might be attributed to the differences in weather factors (temperature, relative humidity) and / or the effect of the common natural enemies in each season. Generally, the tomato leafminer, T. absoluta is found in tomato plants on all tomato growing plantations (winter and summer plantations).
3- Distribution of the tomato leafminer on tomato plant
Generally, the factorial design was used to examine the significant difference in infestation among two tomato hybrids at three levels of leaves on the tomato plant, as well as an interaction may be found between the two variables. The results indicated that the infestation at the oldest leaves (at the low level) was superior over those on either middle or high positions of the leaves.
4- Multi-correlation analysis of some factors affecting the tomato leafminer
Data obtained from the winter plantations indicated that the infestation began when the plant age reached about one month after transportation. It reached the maximum number (about 20 larvae per 10 leaves) after about 45 days regardless of the tomato hybrids. After that the infestation was decreased gradually till the end of the season. It was found that the plant age came in number one with a relative efficiency of about 30% out of 81% of the total efficiency (8 variables). Also, mirid bugs seemed to be responsible for about 6% of the variability in the infestation with T. absoluta larvae. Mirid bugs came in the rating sort in number five. Rating sort of co-efficient of determination indicated that the air temperature occupied the two and three degrees for 448 and super-jakal, respectively. It was found that air temperature is responsible for about 17% and 12% of the variability of larvae infesting hybrids 448 and super-jakal, respectively. The minimum relative humidity was found to be in the lowest degree.
5- Susceptibility of the tomato hybrids to T. absoluta infestation
The tomato leafminer infestation was more abundant during 2012-2013 season than that during 2013-2014 season. Number of larvae per leaf was 75.01 and 27.33 on super-jakal hybrid at 2013 and 2014, respectively comparing with 110.21 and 31.29 for 448 hybrid, respectively.
The statistical analysis of t- test in pairs suggested the significant difference of TLM infestation among the two tomato hybrids, since the 448 hybrid was more favorable than super-jack all over the encountered inspected dates, during the two years of investigation.
from the present data it seemed that the variety of 06 was more susceptible to infestation by T. absoluta more than the variety of 07 however, it is clear that the two varieties went in a parallel manner.
6- Effect of some insecticides on the tomato leaf miner
In general, Coragen 20% Sc gave best results than all other pesticides, therefore Coragen 20% Sc 60 ml / feddan is recommended against the tomato leafminer in tomato plants at Assiut. The tomato plants should be regularly monitored for the tomato leaf miner attack and if the pest’s number increased the crop should be sprayed with recommended insecticide and recommended dose.