| Titles |
|
English :
|
Effect of insecticide treatments on some pests of Vegetables and their associated predators
|
|
| Abstract |
The present study covered an investigation of cucurbit pests and associated enemies under field conditions and the efficiency of a predator under laboratory conditions including the following points with the results indicated in each case.
A. Field studies:
1. Survey and detection of insect and mite pests and their associated natural enemies an cucumber and squash plants:
Survey of insects and mites infested cucumber and squash plants and their associated natural enemies were achieved in some cultivated areas in El- Kanater El-Khaireia, Qualubia Governorate. The studies were carried out during two successive years having two plantation seasons. Aerial sweeping nets and direct inspection of plants were used in this study. The surveys were demonstrated 40 species belonging to 21 families and 11 orders. The most important species recorded on cucumber and squash plantsare 27 species as pests and 13 species as natural enemies. They include 11 foliage feeders, 14 sap-sucker species and 2 root-invadors.
All species listed were identified for their common name, scientific name, site of infestation, frequency and stretch period of occurrence. The most important pests surveyed on squash and cucumber plants are whiteflies, aphids, mites, leafhoppers and thrips, while the natural enemies are numerous but of low densities.
The results indicated that cucumber and squash crops are attacked with insect pests and mites throughout the year. The maximum numbers of insects and mites were captured during summer and autumn seasons (March and October). However, the density of the associated predators and parasites showed of low level at the same stretch period from March to October.
2. Population dynamics of some insect, mite pests and a predator on squash and cucumber plants:
Population dynamics encompasses the study of variation in population numbers in time, space or both and the process responsible for this variation. With any species a number of factors have the potential to influence these processes either directly or indirectly.
The fluctuations of the population densities of pests and an important predator were achieved in winter and summer plantation seasons for two successive years.
Different samples methods were conducted weekly including yellow sticky traps and direct inspection of leaves. The studies were included the seasonal occurrence of the aphid Aphis gossypii, the whitefly Bemisia tabaci, the thrips Thrips tabaci, the leafhopper Empoasca decipiens, the spider mite Tetranychus urticae and the predator Scymnus sp.
The above pests are greatly differed in their abundance and population densities in relation to the plantation season or the kind of plant itself. In other words, these variations may be attributed to different factors which give them a chance of reaching a high level of abundance as population competitiveness or high or low levels as the climatic factor fluctuations.
In general, the results indicated that the whitefly B. tabaci is the major important pest during the two plantation seasons followed by the aphid A. gossypii and then the leafhopper E. decipiens. The thrips T. tabaci and the spider mite T. urticae were existed at very low level during two investigated years to be considered of little economic importance. The pests are always varied according to the plantation season.
In general, almost the recorded pests were reached their maximum level during winter plantation season on squash and cucumber crops. It is well known that the prevailing of pests and the population densities are greatly related to different factors including climatic factors, cultivation practices, kind of plants and soil, plant varieties, ..... etc.
Almost no great significant differences were recorded on the pests and the predator throughout two successive years studied either during the summer plantation season or winter plantation season indicating that the sampling techniques used in the present investigation are effective tools for estimating the different species studied on cucumber and squash crops.
3. Population of pests and a predator under oil and pesticide stress:
The present investigation dealing with comparative studies on the effect of insecticide (actellic) and mineral oil (super masrona 4) treatments on the population of pests and associated predator in squash and cucumber fields.
In general, oil treatment had an equal effect on all pests and associat¬ed predator in squash and cucumber fields. The weekly treatments of both substances apparently caused significant reductions in pest populations. Very promising results have been obtained with oil treatment alone against adults and immature stages of some pests. The oil seems effective as insecticide and acaricide. At least the insecticide can be used in conjunction with oil to reduce the amount of the chemical insecticide in the field. However, it must has great safety to other organisms including man. Therefore, much remains to be done to develop and improve its formulation.
B. Laboratory studies:
1. Predaceous capacity of Orius albidipennis (Reut.) nymphs and adults:
Laboratory rearing method concerning the feeding capacity of O. albidipennis males and females was estimated independently for nymphs and adults. They were maintained at 25±2ºC and 65±5% R.H. and reared
on different species of prey. There are an agreement of the both sexes of O. albidipennis in their food preference. The female O. albidipennis consumed more preys during the nymphal stadia than during the life span of adults. However, the daily consumption during the five nymphal stadia and adults were varied being gradually increasing in consumption rates during successive nymphal stadia were observed. The last nymphal instars of male and female consumed preys more or less as adult bug. In all experiments the predator preferred the nymphs of the mite T. urticae as prey followed by the whitefly B. tabaci and then the aphid A. gossypii.
2. Effect of feeding on the duration of nymphs and life span of the adult Orius ttlbidipennis (Reut.):
Individual of male or female nymphs and adults reared independently in laboratory at 25±2°C and 65±5% R.H. on A. gossypii, B. tabaci and T. urticae nymphs revealed that adult longevity was not affected by the type of prey. The longevity of female was ranged between 13.90 ±1.06 and 18.40 ±1.67, while the longevity of male was ranged between 12.70 ± 1.56 and 14.50 ±1.53. In all experiment the shortest longevity was associated with feeding upon the whitefly nymphs, while the longest one was produced by feeding on the nymphs of the mite T. urticae.
The duration of the five nymphal instars of O. albidipennis was also estimated by rearing the nymphs on the nymphs of aphid, whitefly and the mite T. urticae. The results were always significant between the mite and the other two species. The total duration period of nymph became slightly longer in association with feeding on mite than on aphid or whitefly. However, in all experiments the results recorded on the duration of nymphal stadia reared on A. gossypii and B. tabaci nymphs are not significant indicating the similarity of the aphid and whitefly nymphs as food and feeding requirements.
In conclusion the aphid A. gossypii, the whitefly B. tabaci and the mite T. urticae nymphs are more appropriate preys for the development of this predator. The mite nymphs of T. urticae were preferred as food and feeding requirements for the predator O. albidipennis since the feeding capacity of nymphal and adult stages is more and life span of adults became obviously longer.
|
| Publication year |
1996
|
| Availability location |
معهد بحوث وقاية النباتات
|
| Availability number |
|
| Organization Name |
Plant Protection Research Institute (PPRI)
|
| Country |
Egypt
|
| Publisher |
Name:
كلية العلوم - جامعة عين شمس
Place:
جامعة عين شمس
|
| Author(s) from ARC |
|
| Agris Categories |
Pests of plants
|
AGROVOC
TERMS |
Aphis gossypii.
Bemisia tabaci.
Cucumis.
Cucurbitaceae.
Empoasca.
Insecticides.
Orius.
Pests of plants.
Predator prey relations.
Predators.
Scymnus.
Tetranychus urticae.
Thrips tabaci.
|
| Proposed Agrovoc |
orius albidipennis;
|
| Publication Type |
Master Thesis
|