Effect of cotton bollworm (Helicoverpa armigera Hübner) caused injury on maize grain content, especially regarding to the protein alteration.

The cotton bollworm (Helicoverpa armigera Hübner), which migrated in the Carpathian-basin from Mediterraneum in the last decades, is becoming an increasingly serious problem for maize producers in Hungary. In several regions the damage it causes has reached the threshold of economic loss, especially in the case of the sweet maize cultivation. The aim of the research was to determine the changing of ears weights and in-kernel accumulation and alteration in grain as a function of cotton bollworm mastication.Our investigation confirmed that there is an in-kernel and protein pattern change of maize grain by cotton bollworm. Our results proved the significant damaging of each part of ears by cotton bollworm masticating (the average weight loss of ears: 13.99%; the average weight loss of grains: 14.03%; the average weight loss of cobs: 13.74%), with the exception of the increasing of the grain-cob ratio. Our examinations did not prove the water loss - that is the "forced maturing" - caused by the damage. Decreasing of raw fat (control: 2.8%; part-damaged: 2.6%; damaged: 2.4%) and starch content (control: 53.1%; part-damaged: 46.6%; damaged: 44.7%) were registered as a function of injury. In contrast, the raw protein content was increased (control: 4.7%; part-damaged: 5.3%; damaged: 7.4%) by maize ear masticating. The most conspicuous effect on protein composition changing was proved by comparison of damaged grain samples by SDS PAGE. Increased amounts of 114, 50, 46 and 35 kDa molecular mass proteins were detected which explained the more than 50% elevation of raw protein content. The statistical analysis of molecular weights proved the protein realignment as a function of the pest injuries, too.

Study on weevil pests of oilseed rape at Keszthely, Hungary.

One of the most important pests of rape in early spring are weevils (Ceutorhynchus spp.). The aim of our studies was to identify the occurring weevil species and to study their emergence, swarming, mating and damage. Our observations were performed on an experimental plot at Keszthely (Hungary, Zala County) in early spring of four consecutive years. Following species were collected and identified: Ceutorhynchus pallidactylus MARSHAM, Ceutorhynchus obstrictus MARSHAM, Ceutorhynchus napi GYLLENHAL, Ceutorhynchus pleurostigma MARSHAM. The obvious dominance of C. pallidactylus and C. obstrictus was detected. Their frequency of occurrence was 88-90% among the identified adults. We found that C. obstrictus was the last species to settle. Complete developmental period was 68 +/- 7 days in case of C. pallidactylus and 70 +/- 7 days in case of C. obstrictus. Average number of eggs laid by one female was 176 +/- 23 in case of C. obstrictus and 21 +/- 6 in case of C. pallidactylus.

Comparison on DNA patterns of different ecotypes of European corn borer (Ostrinia nubilalis Hübner) in Hungary.

For a molecular genetic study on Hungarian populations of European corn borer L5 stage larvae were collected from 14 places of three different regions of the country (uni- and bivoltine ecotypes). Additionally, the study included larvae from Egypt, too (multivoltine ecotype). Molecular examinations of European corn borer larvae using the study of mitochondrial cytochrome b (cyt b) revealed that by single strand conformation polimorphism (SSCP) the populations found in Hungary represented the same haplotype. Even the Egyptian sample showed no genetic divergence. Some minor deviatons were found in the case of a sample from Székkutas, but that did not prove the genetic divergence of the bivoltine ecotype either, since the other samples of South-East Hungary did not display this kind of genetic variation. On the basis of our investigations it can be said that the univoltine and bivoltine generations, have uniform genetic complements.