Eucalyptus trees and the use of agrochemicals
Agricultural defensives, also known as agrochemicals or pesticides, are used to avoid or reduce the damage caused by pests, disease, and weeds. Eucalyptus trees, like other agricultural crops, require the use of defensives to maintain economically sustainable production.
When growing eucalyptus, chemical control is only used in two situations: 1) for the control of weeds during the initial phase of plant development (i.e. until the 2nd year), and 2) if an attack of pests or disease causes losses that approach the level of economic damage (calculated by comparing the costs to control the pest/disease to the losses incurred as a result of the damage).
Agricultural defensives are not normally applied as a preventative measure for the control of pests and diseases. This thinking is quite different from what is normally the case for other agricultural crops (as coffee, potatoes, strawberries and tomatoes, among others) in Brazil which use preventive applications of defensives in significant amounts.
For eucalyptus plantations, when a chemical intervention is required, it is preferred that products of low toxicity be applied, according to the technical recommendations of the supplier. All safety procedures are followed for the handling, transport, storage, application, and disposal of the packaging. Handling of agricultural defensives is restricted to trained personnel who are properly protected with the safety equipment required by health authorities.
As a direct consequence, the reduction in the consumption of agricultural defensives has been constant. Invasive plants - The growth of weeds can significantly compromise the development of a eucalyptus plantation mainly during the first two years of growth. This negative impact on growth can extend until the end of the productive cycle. Aracruz uses several control methods, including herbicides. However, the average consumption of herbicides within the company’s plantations is much lower than for other crops (Table 6).
Diseases - One of the most important events leading to the development of genetic resistance for the control of eucalyptus diseases occurred at Aracruz in the 1970’s. The plantations were severely attacked by a disease known as "eucalyptus canker", caused by the Chrysoporthe cubensis mushroom which rots the trunk of the trees. Due to its severity, the disease could have jeopardized the company's forest feasibility. However, measures were taken to introduce species of resistant eucalyptus (mainly E. grandis from Atherton, Australia; E. urophylla from the Flower City in Indonesia, and their hybrids).
Aracruz uses chemical control of diseases only in the seedling production phase in its nurseries. Even here, the use of chemicals is integrated with other practices (e.g. using water and other substances that are free of fungi and bacteria; sterilizing tools and trays; and proper irrigation control).
Pests - Two specific cases can be mentioned regarding Aracruz's approach to pests in the field: the control of
leaf-cutting ants and the Australian eucalyptus snout weevil, that attacks the trees and causes the leaves to fall, limiting
tree growth or its death.
1)The use of formicides (specific insecticides for ant control) varies, depending on which development phase
the plants are in, and is applied when periodic monitoring of the anthill activity indicates a need for ant control.
For example, it is possible to live with higher levels of infestation when the forest is adult. This reduces the amount of
formicide applied per unit of area.
MIPIS is an innovative solution, patented by Aracruz, to combat ants in eucalyptus plantations. It is a portable,
biodegradable microbait dispenser, manufactured and marketed since 2000. It consists of a sachet made of waterproof pulp,
impregnated with a natural substance that attracts only the ants and avoids accidental ingestion by other animals.
The advantage in relation to conventional bait dispensers is that the material is biodegradable. The baits active ingredient
is sulfluramide, which is considered a lowtoxicity substance and does not have an equally effective substitute.
