INVESTIGATIONS CONCERNING THE CORN EARWORM EXTERNAL MORPHOLOGY PUBLISHED

Ioan Pălăgeşiu, Narcisa Crista
The corn earworm (Helicoverpa armigera Hb.) is a cosmopolitan, widespread species. The pest is a very harmful in Asia (India, China), Africa, Australia, and in the last time in Eastern and Central Europe between northern latitude 46º and 47º Helicoverpa armigera Hb. is a recently identified pest of the maize cultivations from the Romanian West Plain. The pest’s caterpillars are little known in zone and frequently are mixed up with other species. In this context the work bring some contributions to knowledge of some external morphological peculiarities for better pest identification. In all European zones in which were signalled the corn earworm attacks, complexes investigations were carried out. In our country the researches are incipient or in some regions are absent. The researches were effect on the larvae and pupae, collected in four years from the maize cultivation of S.D. Timişoara. On the larvae ages, the body length and the head - capsule diameter of the caterpillars and also, pupae body length were measured. The obtained results were statistical interpreted. So data are absent in our country. According to obtained results the body length of the mature larvae (L 5 -L 6 ) oscillated between 23,00 mm and 45,00 mm and for young larvae (L 1 -L 2 ) between 1,50 mm and 10,00 mm. The head capsule diameter was in average 0,37±0,064 for young larvae (L 1 -L 2 ) and 2,53±0,50 for mature larvae (L 5 -L 6 ). The pupae body length was in average 18,8±0,19 and varied between 15,00 mm and 20,00 mm. New obtained data can be compared with the existent data from neighbouring countries where the pest caused important damages. The knowledge of the larvae ages depending by the body length and head - capsule diameter are necessary data in prognosis and warning activity for the optimal treatment application moment establishment. The obtained results contribute to the existent knowledge completion concerning the external morphology, of the new maize pest and generally for plant protection from Romania.
corn earworm; maize; larvae; pupae; body-length; head capsule; diameter; age; treatment warning
Presentation: oral

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