Effect of canopy cover on development of cedar (<i>Cedrela fissilis</i>) and aspects of damage caused by <i>Hypsipyla grandella</i> in agroforestry system

Abstract

Effect of canopy cover on development of cedar (Cedrela fissilis) and aspects of damage caused by Hypsipyla grandella in agroforestry systemEfeito da cobertura sobre o desenvolvimento do cedro-rosa (Cedrela fissilis) e nos danos causados por Hypsipyla grandella em sistema agroflorestal AbstractCedrela fissilis (Vell.) is an important wood species, native to South America. It is appreciated for its physical characteristics and, therefore, its native specimens are overexploited. Commercial cultivation initiatives have been continuously flawed as a result of the damage caused by mahogany shoot borer Hypsipyla grandella (Zeller, 1848). Planting under shaded sites has been one of the management methods used to reduce insect attacks. However, the reason why mahogany shoot borer does not attack shaded plants as often is still unknown. Therefore, the aim of this research was to find cultivation parameters that could combine proper plant development and low rate of attacks by Hypsipyla grandella. For this purpose, increases in height and shoot diameter of cedar seedlings, planted in agroforestry systems, were monitored for the two first years. Three canopy cover rates, namely, 0-20%, 20-40% and 40-60%, were tested for plant development and frequency of attacks by Hypsipyla grandella. The adult population of the insect was monitored with semiochemicals throughout the experimental period, and two pheromonal blends and one food bait were tested. Field results showed that one of the pheromone blends was efficient in identifying small variations in the population of adult specimens. Regarding to the plant development, the treatment with the highest cover rate showed the lowest parameters compared to the intermediate cover. The frequency of attacks by Hypsipyla grandella was greater in the treatment with the lowest cover (0-20%). The results suggest that in canopy cover, ranging from 20 to 40%, good rates of initial development of plants can be combined with low frequency of attack by Hypsipyla grandella.

Establishment and Natural Regeneration of Native Trees in Agroforestry Systems in the Paraguayan Atlantic Forest

“…The higher growth rate of C. trichotoma compared to the other species is consistent with previous observations [78], and in part it may reflect that the tree participates in mutualism with Hymenoptera, as it was found between Cordia eliodora and Astecas ants [79]. Conversely, the low growth rate of C. fissilis can be attributed to attacks by Atta sexdens and H. grandella, as reported in several studies [80,81]. The higher growth rate in the conventional agronomic system in Caaguazú may be attributable to soil characteristics (Table S5), such as texture, structure, soil moisture, and fertility [82], which favor moisture retention, which in turn promotes water consumption and plant growth [83] or forms of eradication of competitive weeds [84].…”

Detection and estimation of Mastigimas anjosi (Hemiptera: Calophyidae) populations on Cedrela fissilis trees

“…The quality of the wood has led to an increase in planting of cedar. However, several insects have been reported as C. fissilis pests, including the mahogany shoot borer, Hypsipyla grandella Zeller, 1848 (Lepidoptera: Pyralidae) that damage this species, especially in dense plantations without shading [10][11][12].…”