Impact of certain weather factors and plant age on the population density of Aphis craccivora (Koch) on faba bean plants.

Abstract

Field studies were done on faba bean plants at the El-Mattana Agricultural Research Station in Luxor Governorate, Egypt, throughout two successive growing seasons (2019/20 and 2020/21) to investigate the seasonal activity of the cowpea aphid, Aphis craccivora (Koch) (Hemiptera: Aphididae) (Giza 843 cultivar). As well, estimate the effects of some climatic conditions and plant ages on the seasonal abundance of A. craccivora. In this study, two insect expressions were used, i.e., insect numbers and incidence of infestation, which articulated the population of this pest. Results indicated that A. craccivora infested faba bean plants from 21 st November 2019 to 12 th March 2020 during the first growing season and from 22 nd November 2020 to 13 th March 2021 through the second one. For the two growing seasons, the cumulative counts of A. craccivora were 321.48 and 340.66 individuals each season, respectively. Furthermore, the overall mean of A. craccivora population was 18.91 ± 0.92 and 20.04 ± 1.52 individuals per 10 plants, during the first and second growing seasons, respectively. As well, the general average of the percentages of abundance was 66.73 ± 1.60 and 58.43 ± 2.28 for the two seasons, respectively. Climatic conditions of weekly inspection dates were more favourable for A. craccivora to increase its population in November, January and February for the two seasons. Additionally, in two consecutive growing seasons, the number of A. craccivora disappeared during the faba bean maturation stage in end March. According to the findings, the combined impacts of environmental conditions and plant ages can explain changes in A. craccivora population density. The results revealed that the effects of weather conditions and plant ages on population density and infestation incidence percentages by A. craccivora were highly significant during the two seasons studied, and that these parameters varied from season to season. Also, the dew point and mean daily minimum temperature were the most effective variable for the changes in the insect population and the percentages of infestation incidences under the studied seasons. These information can aid in the development of an aphid IPM program for faba bean plants.

Impact of Sowing Dates and Relation to the Population of Aphis craccivora (Koch) on the Broad Bean (Vicia faba L.) under Climate Changes

“…In determining insect population dynamics on a host plant, ambient temperature, natural enemies of insects and host plant status are key factors. In addition, Mohamed, et al (2021) the Results indicated that A. craccivora infested faba bean plants from 21 st November 2019 to 12 th March 2020 during the first growing season and from 22 nd November 2020 to 13 th March 2021 through the second one. According to the findings, the combined impacts of environmental conditions and plant ages can explain changes in A. craccivora population density.…”

Population density of the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) and its response to some ecological phenomena in maize crop

“…According to Bakry et al (2020) and Mohamed et al (2021), the weekly variation rate within FAW population was estimated as follows (Formula 2): ( )…”

“…A third-degree polynomial equation was established to represent these relationships (i.e., age, age 2 , and age 3 according to the sampling dates). The following formula was applied: Y = a ± b 1 X 4 ± b 2 X 4 2 ± b 3 X 4 3 (Bakry et al, 2020;Mohamed et al, 2021). According to Fisher (1950), data were statistically analyzed, by using different models of correlation and regression, to find out the relationships between the main weather factors and plant ages (independent variables), the numbers of egg masses, the larval population density, and percentages of damaged plants (as dependent variables).…”

Population Dynamics on The Main Faba Bean Insect Pests in Relation to Certain Ecological Factors in Kafr El-Sheikh Region, Egypt.

“…temperature and average temperature r= -0.61, and -0.57 for the 2010 season, whereas maximum temperature, minimum, and average temperature were negatively insignificant correlations in the 2011 season. Mohamed et al (2021) reported that the partial regression values for the effect of daily mean max. the temperature on the A. craccivora population were a significant positive relation (P. reg.…”