Parameters analysis of the Ostrinia nubilalis Hbn. attack at maize crops in the conditions of central Moldova

Abstract

Maize is cultivated on 2,678.5 thousand ha in Romania, and its cultivation on large areas attracts a number of pests that attack various parts of the plant in different developmental phases. One of these dangerous pests is Ostrinia nubilalis Hbn., a species that occurs during the growing season of maize and causes production losses by the attack on the stem and cob. The larvae produce various attacks, influenced by climatic conditions, the frequency of attacked plants being between 15.7 and 67.9% in the south-west of the country, in the south-east of the country varies between 43.3-79.4%, in the Transylvanian Plain has values between 60.00% and 81.88%, in the west of the country the attack is around 41%, and in the east of the country by 30.20%. The importance of attacks by Ostrinia nubilalis Hbn. at maize led to the initiation of studies in 2019 at the A.R.D.S. Secuieni to determine the influence of technological factors on the parameters of attack (frequency of attack, average number of holes, galleries and larvae and average length of gallery) produced by larvae. For the maize sown in epochs, the optimal epoch, the IIIrd, recorded the lowest values of the parameters: the frequency of the attack was 18.65%, were identified 0.60 holes/plant, 0.39 galleries/plant and 0.38 larvae/plant, and the average length of the galleries was 8.39 cm. The behavior of genotypes at the attack produced by larvae varied within very wide limits, the frequency of the attack was between 36.56% at the early genotype Vibrion and reached 48.50% at the late genotype Olt.