Silvicultura de precisão no monitoramento e controle de formigas cortadeiras em plantios de Pinus.

Abstract

A control and monitoring study of leaf-cutting ants was done in Pinus plantation areas from Bosques del Plata company, Argentina. The research was divided into five chapters: Chapter I Species of leaf cutting ants in the Pinus spp. plantation, Corrientes-Argentina: to identify the species in the field plantation 2004; to verify what are the prevailing species, more abundant, dominant and dispersion according to associated characteristics; to define the monitoring strategies. Six species of leaf cutting ants were found, mainly Acromyrmex heyeri (97,75%). Chapter II The genus Acromyrmex sampling plan in pre-planting areas; to study the nests spatial distribution; to determine the adequate size of sampling plot and the sampling intensity. The results allow to conclude that the nests spatial distribution is randomized and the adequate size of sampling plot for the Acromyrmex (n.ha-1) is 700 m2 and the adequate sampling intensity for the plots is 10,5% for a predicted error of 24%. Chapter III - Pinus taeda and Pinus patula resistance to leaf cutting ants: to know the secondary compounds associated to cut preference; to verify the young needles chemical compounds difference when contrasted with older needles from the tree. The results show that the young needles are more prone to cut; the monoterpenes α-pinene, β-pinene, α-tujene, myrcene and limonene, are only in the Pinus taeda (27 months) older needles (non attacked); the eudesmol show a more significant concentration decrease in the sample of needles from Pinus taeda seedlings, attacked by leaf cutting ants. Chapter IV Evaluation of Pinus taeda development after leaf-cutting ants attack: to evaluate the damage that leaf-cutting ants could be causing in Pinus taeda seedlings; to evaluate deficiency in height and diameter development and productivity index in Pinus taeda plants in the following stages: Year 0, Year 1 and Year 2. The results allow to conclude that A. lobicornis and A. heyeri attacked 20,8% of the new planted (65 days) Pinus taeda seedlings. There is a significant difference in the development of Pinus taeda plants in the Year 0 and Year 1 when compared with Year 2. Chapter V Leaf-cutting ants control: to evaluate the efficiency of different doses from Citromax formicide in Acromyrmex heyeri and Acromyrmex lundi control; to evaluate the efficiency of different formicides in Atta sexdens piriventris control. It was possible to conclude that there wasn t influence of the nest size when related to the control percentage of Acromyrmex heyeri and Acromyrmex lundi. The Citromax, at least 10g/nest controls 100% of the Acromyrmex heyeri and Acromyrmex lundi nests. In Atta sexdens piriventris control after 90 days, the formicides Citromax, Atta Mex-s and Landrex Plus showed a percentage of 83,3%, 83,3% e 100%, respectively.