In Egypt, maize is an important crop that is attacked by various pests. In the present study, the effect of maize planting dates on the populations of insect pests and their natural enemies were investigated throughout the growth stages of maize plants. The maize planting dates were at the beginning of May, Jun, and July in the 2019 season and were repeated in the 2020 season. Samples were collected weekly to determine the populations of the insect pests, Limothrips cerealium (Haliday, 1836), Rhopalosiphum maidis (Fitch, 1856), and Sesamia cretica Lederer, 1857 and their natural predators. For the first sowing date, the infestation percentage of L. cerealium and S. cretica were most substantial, especially in the seedling and precorn formation stages. For the third sowing date, the number of R. maidis was most substantial, especially in the corn formation stage. Three predators were associated with these insect species; of these predators, Coccinella undecimpunctata (Linnaeus, 1758), Scymnus interruptus (Goeze, 1777), and Chrysoperla carnea (Stephens, 1836) were observed at the highest numbers during all sowing dates. A highly significant correlation existed between populations of S. interruptus and the three insects across the two seasons. Data suggest that the percentage of thrips, aphids, and stem borers infestations can be minimized by planting maize varieties in June.
The experiment was conducted to study the seasonal abundance of the most important insect pests of maize and its relation with natural enemies and weather factors in Assiut governorate during 2019 and 2020 seasons.The samples were examined from June to September to determine the population of Limothrips cerealium (Haliday, 1836), Rhopalosiphum maidis (Fitch, 1856) and Sesamia cretica Lederer, 1857 and its the associated predators. The population of L. cerealium recorded a peak in the 4th week of July 2019 and the 1st week of August 2020. The highest population of R. maidis occurred in 1st week of September at both seasons. The simple correlation and regression between L. cerealium population and three weather factors were insignificant in both seasons while S. cretica population were found to be significant with R.H%. The population of R. maidis in the 1st season was insignificant negative with temperatures but was significant in the 2nd season. The plant age was more effective than the weather factors on the population of the three insect pests. The common predators were Orius albidipennis (Reuter, 1884) and Scymnus interruptus (Goeze, 1777)which were highly significant with all three insect pests.
Maize considered one of most important cereals in Egypt that used in consumed directly by humans. It is attacking by different insect pests and most important of these insects, aphids, thrips and corn borer that was influence yield size and quality. Field experiments were planted in early June 2019-2020 seasons at Assiut Governorate. Current study, effects of three fertilizers systems (synthetic, organic and mixture between synthetic and organic fertilizers) and three planting densities (5, 10 and 15 plant/Linear meter) on the population of insects and yield were investigated. Results indicated that mixture fertilizers had lowest mean number and infestation percentage of three tested insects at two seasons. Infestation% was higher in 1 st than 2 nd season. Mean numbers of thrips at mixture fertilizers were a highly significant than both synthetic and organic fertilizers. Addition that, highest yield of maize was recorded in mixture fertilizer at the two seasons (3783 and 3948 kg/feddan, respectively). Results showed that, mean numbers of three insect pests were increased with increasing plant density/Linear meter at the two seasons. Thrips population and aphids were significantly differences in three plant densities (5, 10 and 15 plants/Linear meter) at the two seasons. The highest yield of maize in medium plant density (10 plant/Linear meter) recorded 3655 and 3768 kg/fed., at 2019-2020 season respectively. It is concluded that mixture fertilizer and plant density was 10 plants/Linear meter recorded lowest population of three tested insects and high yield of maize at the two successive seasons.
In Middle and Upper Egypt, sugar-cane plants are subjected to infestation with the Purplelined stem borer, Chilo agamemnon Bles. (Lepidoptera: Pyralidae). This paper contributes to the pest's status on sugar-canes of the commercial variety "GT.54/C-9" just prior milling in 4 milling factories. Aspects considered throughout two successive milling seasons (1996 & 1997) were the rate of infestation in El-Minia, Souhag and Quena Governorates, the rate of infestation on plant-cane, 1 st , 2 nd , and 3 rd ratoon plantations, the distribution of infestation on the different parts of sugar-cane stalk and stalk breakage. The highest rate of infestation occurred in Souhag and the lowest rate took place in El-Minia while the rate of infestation in Quena was slightly higher than it in El-Minia but comparatively less than in Souhag. Plant cane was the most susceptible plantation and the 3 rd ratoon was the least susceptible plantation while the 1 st and 2 nd ratoon canes were subjected to intermediate infestation rates. Infestation was concentrated at the lower and middle thirds of the stalk. Roughly, about one third of the infestation took place on the lower third of the stalk and about one half of it occurred on its middle third whereas less than one sixth of the infestation was recorded on the upper third of the stalk. Stalk breakage occurred anywhere along the stalk but it mostly happened at the upper third and to a relatively less extent at the middle third while it rarely took place at the lower third of the stalk.
http://eajbsa.journals.ekb.eg/ The Impact of Temperature on life-history traits of the bird cherry-oat aphid, Rhopalosiphum padi (Hemiptera: Aphididae) reared on wheat seedlings
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