Leaf-cutting ant attack in initial pine plantations and growth of defoliated plants

Mariane Aparecida Nickele,Edson Tadeu Iede,Wilson Reis Filho,Nádia Caldato,Edilson Batista De Oliveira,Priscila Strapasson

doi:10.1590/s0100-204x2012000700003

Mariane Aparecida Nickele, Edson Tadeu Iede + Show 4 more

Open Access

https://doi.org/10.1590/s0100-204x2012000700003

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Abstract

The objective of this work was to evaluate the natural attack by Acromyrmex crassispinus in initial Pinus taeda plantations without control measures against ants, as well as the effect of defoliation in seedlings of P. taeda. Evaluations of the attack of leaf-cutting ants on P. taeda plantations were done monthly in the first six months, then 9 and 12 months after planting. The percentages of plants that were naturally attacked by ants were registered. The effect of defoliation was evaluated by artificial defoliation, simulating the natural patterns of attack by A. crassispinus on P. taeda seedlings. The natural attack of A. crassispinus was greater during the first months after planting, being more intense in the first 30 days. Artificial defoliation indicated that there were no significant losses in diameter and height in plants with less than 75% defoliation. However, there were significant losses in diameter and height in plants with 100% defoliation, independently of the cut of the apical meristem, and also plant death. The control of leaf-cutting ants in P. taeda plantings, in which A. crassispinus is the most frequent leaf-cutting ant, should be intense only at the beginning of planting, since the most severe attacks occur during this time.

Highlights

In Brazil, approximately two million hectares are planted with different Pinus species
In a study in Argentina, 20.8% of the recently‐planted P. taeda seedlings were attacked by A. heyeri and A. lobicornis, during the first 65 days after planting, but there was a reduction in the herbivory rate along time, as observed in the present study (Cantarelli, 2005)
More than 50% of the needles of P. contorta were harvested by leaf‐cutting ants in northern Patagonia, Argentina, and there was a complete defoliation of seedlings (Pérez et al, 2011)

Summary

Introduction

In Brazil, approximately two million hectares are planted with different Pinus species. In the South of the country, about 80% of the planted forests consist of Pinus taeda, due to the high productivity and quality of the raw materials (Abraf, 2011). The implementation of development plans to expand the forest base with fast‐growth species contributes to industrial enterprises (Hoeflich, 2004). Extensive planting of forest monocultures creates favorable environments for the establishment of insects that can become pests. Among these insects, the leaf‐cutting ants are one of the most important forest pests in South America, considering the damage caused in forest plantings (Cherrett, 1986).

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