چكيده لاتين :
Introduction
Chickpea pod borer worm damages the chickpea crops in countries such as India, Mexico, Australia, the USA, Uganda and Iran. This worm is considered as the main pest in chickpea cultivation. After cereals, chickpea cultivation involves the highest cultivation area in Ilam province and it is of utmost importance regarding the farmers income as well as cultivation sequence plans. In Ilam, Kermanshah, Lorestan and Golestan Provinces, which have a mild winter, therefore autumn cultivation is recommended instead of spring cultivation and while the damage of negative factors is higher in the autumn cultivation, the yield is still higher than the spring cultivation. Regarding chickpea cultivation in Ilam province, there are three different species of Helicoverpathat reducing the yield, which are as follows: (1) Helicoverpab viriplaca, (2) H. armigera and (3) H. peltigera. The species of H. vitiplaca with 94 percent higher frequency than other species is the dominant species in chickpea cultivationby feeding on chickpea leaves and grains, these pests inflict damages. Biological study of chickpea pod borer worm in different plantation dates in Ilam Province showed that the highest larvae and pest density was witnessed during the period between May 10 and May 21. Different varieties of chickpea cultivates in different countries show that the reaction of different varieties to the damage inflicted by the pest has been different; Based on the available literature, there was no reported high resistance against the pest.
Materials & Methods
In order to investigate the effects of the date of plantation and the variety on the density and the extent of damage caused by the pest, this study was carried out using complete randomized block design (CRBD) in split plots with six different treatments and three replications in Shirvan Chardavol research station (Ilam Province, Iran) for two years. The main plots included of two plantation dates in autumn (early November) and spring (late February). Sub plots included of three distinct varieties of chickpea including varieties of Hashem, Arman and Azad. The area of each treatment was three meters by five meters and the row distance was 25 cm, the distance between plants on each row was 10 cm, the distance between plots was 1.5 m and the distance between blocks was 2 m. During farm experiment there was no pest control; however, other factors such as land preparation, weed control, blight control and so on were considered. On May 10 (when the most larvae were present), in each treatment, 50 plants were selected randomly and the number of the pest larvae was measured. Moreover, before crop harvesting in each treatment, 100 plants were randomly selected and the number of produced grains and the number of eaten grains (the damaged grains are inside capsules consisting of a noticeable hole where the larva has entered) were counted. Furthermore, the yield in each treatment was weighted and all the data for the scheme including the average produced grains, the average eaten grains in each plant, the average density of larvae in each plants and the treatment yields were analyzed after the transformation of the data using the GLM procedure with SAS software method.
Results & Discussion
Results indicated that in autumn cultivation, larva density per plant, grain number per plant and yield per hectare were 0.16 larva, 11.8 grains and 436 Kg, respectively, and those in spring cultivation were 0.04 larva, 7.7 g and 288 Kg, respectively. The results from the literature indicate a high yield and performance for the autumn cultivation due to better utilization of soil humidity, flowering acceleration, pod formation acceleration and longer flowering period, which leads to the fact that autumn cultivation be recommended instead of spring cultivation. Therefore, while in this plantation period, the density of the pest has also increased, still the yield is higher than other cultivation dates. The Arman and Azad varieties with yield of 465 and 400 Kg/ha in comparison with Hashem with 233 Kg/ha had the higher yields. The results of different studies have shown that there are no varieties of chickpea with a high resistance towards pod borer worms; however, some of the varieties show lower extents of damage. For instance, in India, the damage in ICC506 genotype was lower than that of ICCC37 genotype. In overall, Kabul (white) genotype was reported to be more sensitive than Desi (black) genotype towards chickpea pod borer worms.
Conclusion
Among the studied plantation dates and varieties, the density, damage inflicted by the pest and the yield, it is concluded that Arman and Azad varieties had the best yield in autumn cultivations.
