Variation in attack by the mahony shoot borer, Hypsipyla grandella (Lepidoptera: Pyralidae), in relation to host growth and phenology

In order to evaluate the relationships between attacks by the mahogany shoot borer Hypsipyla grandella (Zeller) and host growth and phenology, field trials of Spanish cedar Cedrela odorata and American mahogany Swietenia macrophylla established in Costa Rica were assessed intensively over an 84 week period. Height growth of C. odorata was approximately twice that of S. macrophylla, with mean growth rates of 2.0 and 1.3 cm week-1 respectively. Cedrela odorata displayed pronounced temporal variation in leaf phenology, with a minimum of 51 percent of trees in leaf during a relatively dry period. In contrast, the minimum proportion of foliated S. macrophylla trees was 87 percent. No shoot borer attacks were recorded on S. macrophylla until week 50 after the onset of assessments, whereas initial attacks of C. odorata were recorded during week 6. By week 84, the proportion of trees attacked was 74 percent and 77 percent, respectively. In both species, attacks were concentrated in seasonal peaks, coinciden with the production of new shoots. Pronounced spatial variation in attack was observed in both species. At week 12, the number of attacks per block in C. odorata was negatively correlated with available calcium concentration (r=0.85, P<0.001), whereas mean height growth of C. odorata was positively correlated with available phosphate concentration (r=0.84; P<0.001). Significant variation in height to firest damaging attack was observed in both species. By the end of the observational period, only 6 percent of C. odorata and 0.4 percent S. macrophylla remained undamaged to a height of 3 m. It is suggested that control methods for the mahogany shoot borer should take account of temporal dynamics in attack, and relationship to host phenology. Manipulation of the soil nutrient status may also form part of an integrated approach to pest management.

Bibliographic Details

Main Authors:	99140 Newton, A.C., 59048 Cornelius, J.P., 93912 Mesén, J.F., 58999 Corea, E.A., 130731 Watt, A.D.
Format:	biblioteca
Published:	1988
Subjects:	HYPSIPYLA GRANDELLA, CEDRELA ODORATA, HUESPEDES, FENOLOGIA, PLAGAS FORESTALES, COSTA RICA,
Tags:	Add Tag No Tags, Be the first to tag this record!