Studies on the Population Densities of Certain Insect Pests Attacking Grapevine Trees and Their Associated Predators at Mansoura District

Abstract

The present investigation was carried out in the farm of Agriculture Research Center , Faculty of Agriculture, Mansoura University to study the effect of some weather factors on the population density of per certain insect pests infesting grapevine trees and their associated predators during the successive seasons of 2014 and 2015 at Mansoura district. The obtained results revealed that four peaks for Retithrips syriacus Manget season were recorded during the period of study. The highest number for this insect was recorded in the second week of August in the two seasons of study. There were four peaks per season for Empoasca lybica deBerg during the period of investigation. The highest number of E. lybica was recorded in the first and third week of June during the two seasons of study. The obtained results showed that four peaks for Empoasca discipiens Paoli were recorded during the period of study. the highest number for this insect was recorded in the third week of July and in the third week of August during the first and second season of study. Data recorded three peaks for Lobisia botrana Schift during the two seasons of study, and the highest number was recorded in the third week of June in the first season and in the first week of July in the second season of study. There were three peaks for Chryptoblabs. Gnidiella Miller in the two seasons of study the highest number was recorded in the third week of Jun in the two season of study , The obtained result assured that three peaks for Cydonia vicina nilotica Muls in the two seasons of study. The highest number for this insect was recorded in the second week of May in the first season 2014 and in the first week of August in the second season of study. The obtained results revealed that there were four peaks for Coccinella undecimpunctata in the two seasons of study,and the highest number for this insect was recorded in the second week of May in the first season and in the third week of August in the second season of study. There were three peaks for Cydonia vicina isis in the two seasons of study. The highest number for this insect was recorded in the third week of Jun in the first season and in the first week of August in the second season of study. The obtained result assured that the temperature (maximum, minimum and average) positively affected on the population density of the most main insect species except C. gnidiella during the two seasons of study. The relative humidity affected negatively on the population density of these insects .the statistical correlation coefficient between the population density of predatory insects and the temperature and relative humidity showed a highly or slightly significant positive or negatively effect on population density of these insects during the two seasons of study.

Population Fluctuations of the Dominant Pests and Their Associated Predators on Barley Plants

“…The partial regression between C. undecimpunctata population and mean temperature or the relative humidity were (b 1 = 7660 , 0.4330 and b 2 = 0.1207, 0.0925) in the two seasons, respectively. These results partially agree with those of Ghanim et al (2015) and Amer (2016) who found that temperature positively affected the population of C. undecimpunctata.…”

Photoperiodic, thermal and trophic responses of a predatory ladybird Cheilomenes propinqua

“…On the other hand, field studies conducted in various agricultural habitats in several governorates of the Nile Delta showed that seasonal dynamics of population density of aphids (which is the main prey of C. propinqua ), as can be expected, strongly depends on the crop. In particular, on sugar beet, a high aphid population density was observed from October to April (Hegab et al., 2018; Khalifa, 2017), on wheat, in March–May (Helmi & Rashwan, 2013), whereas on grapevine, high population densities of insect pests and their predators (including the object of our study) were recorded in May–September (Ghanim et al., 2015). Thus, it seems that C. propinqua can find a prey throughout the year, although low winter temperatures undoubtedly increase mortality and slow down larval development (Yarpuzlu & Uygun, 2010).…”

“…This polyphagous predator feeds mostly on various aphids, although feeding on soft scales, mealybugs, whiteflies and psyllids was also recorded. It often reaches high population densities and is therefore considered as an important natural enemy of insect pests (Abdel‐Salam et al., 2018; Adly et al., 2016; Atuncha et al., 2013; Badary, 2010; Bayoumy & Michaud, 2015; Catling, 1970; Dicko, 2000; Ghanim et al., 2015; Mahmoud et al., 2016; Sæthre et al., 2011; Youssif, 2019). Thus, large geographic range, wide habitat specificity and broad range of prey (including a number of pests of protected crops) suggest that C. propinqua can be considered as potential agent for biological control in greenhouses, but, as far as we know, this potential has not yet been realized.…”

Signal and Nutritional Effects of Mixed Diets on Reproduction of a Predatory Ladybird, Cheilomenes propinqua

“…Cheilomenes propinqua is known as an active predator of aphids, soft scales, whiteflies, mealybugs, and other small sucking pests. This predatory ladybird shows not only a wide prey range, but also broad habitat specificity reaching high population densities in fields, orchards, vineyards, and other agricultural landscapes [44][45][46][47][48][49][50][51][52][53][54]. Preliminary laboratory studies showed that C. propinqua has a number of desirable properties of a potential successful mass-reared biocontrol agent: rapid pre-adult development (10-11 days), high voracity (depending on prey species, larva consumed a total of about 500 aphids, female consumed 40-80 aphids per day), high lifetime fecundity (about 1000 eggs per female) and prey search activity [20,[55][56][57][58][59].…”