Population Growth of Dysaphis pyri (Hemiptera: Aphididae) on Different Pear Cultivars With Discussion on Curve Fitting in Life Table Studies

Abstract

Population growth parameters of the Dysaphis pyri (Boyer de Fonscolombe) (Hemiptera: Aphididae) were evaluated on four different cultivars (Coscia, Ankara, Williams, and Santa-Maria) of pear (Pyrus communis L.) under field conditions in the Van region of Turkey. Aphids were kept on leaves of 10-yr-old pear trees in Plexiglas clip-cells (20 mm in diameter and 10 mm in height, with the upper side covered with muslin). For the description of the stage differentiation during population growth, we analyzed raw data of developmental time, survival, and fecundity using the age-stage, two-sex life table to take the variable developmental rate among individuals into account. Results indicated that the Coscia and Ankara cultivars are less favorable hosts for D. pyri because of the longer preadult developmental time, higher preadult mortality rate, and lower total fecundity on these cultivars. The intrinsic rate of increase (r), the net reproduction rate (R0), and the finite rate of increase (λ) values were lower on the Coscia and Ankara cultivars. We discussed the application of the Weibull function, polynomial model, and Enkegaard model in life table studies. Because these models are often inaccurate in describing survival and reproduction parameters, we suggest that their application in life table research should be reevaluated.

The Population Growth of Spodoptera frugiperda on Six Cash Crop Species and Implications for Its Occurrence and Damage Potential in China

“…The parameters of life tables often vary with temperature, chemical pesticides and host species [ 36 , 37 , 38 , 39 , 40 , 41 ]. The r summarizes the physiological qualities of an animal relative to its capacity of increase and is often used to compare the fitness of populations across diverse climatic and food-related conditions [ 25 , 42 ].…”

Population growth potential of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) on tomato, potato, and eggplant

“…With the increasing awareness among the growers about advantage of integrated pest management and eco‐friendly insect pest management, studies on life table of important key pests like T. absoluta and their implication in designing newer advanced management strategies are certainly and urgently needed. Population growth parameters of a cohort on various hosts in controlled conditions are useful to asses the biotic potential of an insect facing a new host and to evaluate quality of the host plant (Atlihan et al, ; Pereyra & Sánchez, ) because the insect pest growth rate can be estimated accurately using these parameters. The population growth parameters of T. absoluta on tomato, potato, and eggplant were calculated employing the age‐stage, two‐sex life table which gives accurate as well as more realistic life table because it is capable of describing the differentiation among stages and allows the incorporation of dynamic developmental rates among individuals (Atlihan & Chi, ; Huang & Chi, ; Özgökçe, Chi, Atlihan, & Kara, ; Qayyum, Aziz, Iftikhar, Hafeez, & Atlihan, ).…”

“…Food quality and quantity directly or indirectly affect development, survival, and fecundity of insects, and consequently influences population fitness (Atlihan, Kasap, Özgökçe, Polat Akköprü, & Chi, ; Özgökçe & Atlihan, ; Özgökçe, Chi, Atlihan, & Kara; Polat‐Akköprü, Atlihan, Okut, & Chi, ; Scriber & Slansky, ; Slansky, ). Hence, understanding population growth performance of pests on other crops is necessary for developing effective control strategies.…”

Tri-trophic interactions among nitrogen-fertilized tomato cultivars, the tomato fruit worm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and the ectoparasitoid, Habrobracon hebetor (Say) (Hymenoptera: Braconidae)

“…The results of the present study indicated that host-plant nutrition influenced the parasitoids indirectly and among the 24 tested treatments, the longest larval, and pre-adult durations as well as the lowest, R 0 , T, λ, and r values belonged to E and R, indicating that this cultivar is partially unsuitable or tolerant; however, K and SB seemed to be favorable for development of herbivores and wasps. In fact, the lower (r) and (λ) values observed in the present study can mainly be attributed to the longer pre-adult developmental time, lower fecundity, lower survival rates, and delayed peaks in reproduction (Atlihan et al 2017). Efficiency of wasps declined when herbivores fed on poor nitrogen host plant (Winter and Rostas 2010) and application of fertilizers enhanced the development rate of the parasitoid (Garratt et al 2010).…”