Studies on the shootborer Hypsipyla grandella (Zeller) (Lepidoptera Pyralidae). I. Host selection behavior

Abstract

This paper presents the results of a series of experiments related to host tree selection by adult Hypsipyla grandella Zeller. The objectives were: (1) to investigate adult flight behavior; (2) to study the microclimatic conditions associated with flight; and (3) to determine patterns of borer attack in relation to host tree phenology and potential attractants. Data indicated that, in a plot of Cedrela odorata L. heavily attacked by the borer, adults flew at higher altitudes than aboli, which averaged 0.6 m in height. Another flight pattern was also observed, consisting of short flights from host trees to low ground cover and vice versa. Regarding the relationship between microclimatic conditions and flight, the duration of the study was too short to reach definitive conclusions. However, adults were observed to be flightless when temperatures were below 17°C. Rainfall less than 11 mm did not impede flight. The greatest activity during the study period was recorded after heavy rain.

There are fairly definite indications that the adult H. grandella orients itself to its host by means of smell and that there is a high correlation between the number of attacks per tree and the proportion of fresh leaves.