~ 234 ~ Journal of Entomology and Zoology Studies 2017; 5(6): 234-240 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2017; 5(6): 234-240 © 2017 JEZS Received: 05-09-2017 Accepted: 07-10-2017 Syed Abdul Qadeem Department of Entomology, Faculty of Crop and Food Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan Ata ul Mohsin Department of Entomology, Faculty of Crop and Food Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan Humayun Javed Department of Entomology, Faculty of Crop and Food Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan Ajmal Khan Kassi Department of Entomology, Faculty of Crop and Food Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan Correspondence Ajmal Khan Kassi Department of Entomology, Faculty of Crop and Food Sciences, PMAS Arid Agriculture University, Rawalpindi, Pakistan Effect of two cabbage cultivars on fitness of the most prevalent larval parasitoid of P. xylostella Syed Abdul Qadeem, Ata ul Mohsin, Humayun Javed and Ajmal Khan Kassi Abstract The research was conducted to test the effect of two different cabbage cultivars on development period of larval parasitoid (Diadegma insulare) which were reared on cabbage pest larval population Plutella xylostella in biocontrol laboratory at PMAS Arid Agriculture University, Rawalpindi. The effect of two different cabbage cultivars Golden Acr and Chinese cabbage were tested on the P. xylostella pupae, the calculated value (28.158%) was higher than critical value (4.09%). The significant variation was found in pupal development period (days) and mean pupal population (0.85) per plant both cabbage cultivars. The higher parasitism level (59 %) was recorded on Golden Acr cultivar and the higher fecundity percentage (61%) was observed on Chinese cabbage cultivar. The total development period of female and male of D. insular were recorded (6.34±0.9 and 6.80±) on Golen acr and (6.73±0.20 and 7.04± 0.38 days) on Chinese cabbage. The total longevity of D. insular female was recorded 19.5± 4.32± and 21.32± 1.56± (days) on G. Acr and C. cabbage cultivars and male longevity period of D. insular was recorded (20.3± 5.18 and 21.9± 1.47 days) on both cultivars. The significant difference was observed on both female and male forewing size. The hind tibia of D. insulare female and male were measured (Fcal=17.6, fcri= 4.19) and (Fcal=38.8, fcri= 4.2), respectively. Keywords: Effect, two cabbage cultivars, fitness 1. Introduction Pakistan produces almost all vegetables including cabbage. Due to high nutrition value, cabbage crop is also attacked by a number of insect pests which affects its quality, yield and better look. The most important insect pest of cabbage crop is Diamondback moth (DBM) P. xylostella (Plutellidae: Lepidoptera), recorded from more than 128 countries of the world [1] . P. xylostella caterpillars mainly damage as leaf feeders. At early larval instars, damage is as small irregular holes in the leaves; however, the entire leaf may be eaten by the presence of the larger population of P. xylostella [2] . A lot of damage is due to the construction of tunnels in the head as in cabbage and brussel sprouts. Furthermore, crop damage is usually first evident on plants growing on ridges in the crucifier field. The heavy population of P. xylostella can cause more than 90% crop loss [3] and only few fourth stage larvae on a cabbage can make it unsalable [4 and 5] . Continuous efforts have been made by the breeders and growers to improve cauliflower production. Practically, all the available methods and pest control technologies have been tried at some time or another for the management of P. xylostella [6] . Selection of varieties and crop management practices are the main factors that contribute to growing profitable cauliflower [7] . D. insulare is the principle agent used for the control of P. xylostella globally and having a size of less than 6mm long with reddish brown legs and abdomen. The Female has well defined ovipositor and produce eggs in round shape which lacks projections. The Larva has segmented body with white color and narrow tail [8] . Number of generations of parasitoid in a year depends on the number of generations of the host. P. xylostella host larvae support only one parasitoid larvae and all the larval instars of P. xylostella can be parasitized by D. insulare [8] . The P. xylostella parasitized (70% to 90%) of larvae and consume (35% to 80%) less food than non-parasitized [8 and 9] . While, stages of the larval instars parasitized by D. insulare effect on offspring sex ratio. More males produced when 2 nd instar are parasitized and more females are produced when 3 rd and 4 th instar are parasitized [9] . Parasitoid emerged as a mature larva from the pre-pupa stage of the cabbage host pest. Single female of D. insulare lays total 814 eggs at 23 °C temperature during incubation period.