The relationship between physiological disease, blossom end rot and infestation to cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae) in the tomato fields

Calcium is an important nutrient element for tomato plant, which its deficiency leads to sensitivity to environmental and biotic stress. Helicoverpa armigera is a major agricultural pest, which causes severe yield lose and increases the cost of pest control annually. The current research carried out to study relationship between calcium deficiency of tomato fruits and the infection rate offruits to H. arimigera in two regions of Qazvin province, Abgram and QleShohad area during 2015 cropping season. According to the obtained results, a positive relationship between calcium deficiency and infection rate of fruits has discovered. Calcium deficient fruits were more susceptible to H. arimigera. Also it was found that by increasing fruit size and weight, infection rate to H. arimigera has been decreased, whereas deficiency of calcium in the fruits has been increased. The Highest infection rate was observed during fruit setting, while the highest deficiency rate observed during coloring of fruits. According to the results, it seems that calcium deficiency has an important role in tomato fruit worm damage level. On the other hand, managing plants nutrition with appropriate nutritional requirements at the right time can reduce infestation rate to tomato fruit worm.