Occurence of the cotton bollworm (Helicoverpa armigera Hbn.) in Hungary in 1996, its damage and experiences in its control
1997
Voros, G. (Tolna Megyei Novenyeg. es Talajved. All., Szekszard (Hungary)) | Szeoke, K. (Fejer Megyei Novenyeg. es Talajved. All., Velenve (Hungary)) | Dulinafka, Gy. (Bacs-Kiskun Megyei Novenyeg. es Talajved. All., Kecskemet (Hungary))
The cotton bollworm caused heavy damages in the field crops and horticulture also following the cold and wet winter of 1995/96. It overwintered in somewhat lower numbers than in the previous years but during the summer periodical immigration of adults from neighbouring countries was observed. The progenies of locally developed individuals and of immigrated ones damaged in lower numbers and to a lesser degree compared to 1994/95 but even so heavy damage was observed in some places. The range of its host plants increased: although not originally wheat pests, the larvae destroyed and devoured the milky seeds of winter wheat in Bogyiszlo (Tolna county). The intensities of swarmings were studied by light- and pheromone traps. The number of adults collected showed well the decrease of populations; the low catches of light traps showed throughout the vegetation period the presence of cotton bollworm adults, but more significant numbers were noted by the end of August and early September. The pheromone traps placed into the vicinity of host plants collected in irregular catches only a few adults. The course of flight could be established only by summarizing the catches of several traps. According to the observations the parasitoids of eggs and larvae played a significant role in decreasing the populations as well as the rainy weather that prevented the production of a massive autumn generation that could have caused more severe losses in maize, paprika and other vegetables. Later larvae occurred that had developed on weeds and tobacco plants, but the number of pupae overwintering in the field is not significant. The preparations used in control experiments showed satisfactory results only in cases when they have been applied between the swarming peak of adults and the hatching of eggs. It was established that the data of light- and pheromone traps can present indications for the begin of control if they are completed by individual observations
Показать больше [+] Меньше [-]