CHARACTERIZATION OF INJURY CAUSED BY Coptotermes testaceus IN Tectona grandis PLANTATIONS IN BRAZIL

Coptotermes testaceus (Linnaeus, 1758) is the most important species of heartwood termite of adult trees in forests planted in Brazil. This study aimed to characterize the injuries promoted by the heartwood termite C. testaceus in Tectona grandis commercial stands. Tree bark with extend carton material on the outside, forming external galleries and internal stem with a high termite infestation, was found in August 2018, in clonal plantations of T. grandis of 4.2 and 7.2-year of age. Internal injuries were characterized by galleries inside stem length with the presence of some soil, carton material, and termites inside the galleries. The damage by C. testaceus may not show external signs, and the injury was only detected during the harvesting process.


INTRODUCTION
Tectona grandis L.f. (Lamiaceae) is an Asian tropical hardwood tree with the world highest commercial value due to inherent resistance of its wood (Roychoudhury, 2012), low specific weight, high natural durability, straight trunk, dimensional stability, and aesthetic beauty (Macedo et al., 2005;Moya et al., 2014). In Brazil, this exotic species has an excellent adaptation to the edaphoclimatic conditions (Alcantara and Veasey, 2013) and has been planted since the 1960s (Cruz et al., 2008). Today, the area planted in Brazil corresponds to 87,502 hectares (Ibá, 2017) and Macedo Neto et al. (2020) have investigated teak plantations growing even in north of the country.
The production of T. grandis can suffer losses at any stage of its development due to insect attack (Kulkarni et al., 2009). T. grandis was commonly attacked by termites, which are considered important pests in forest plantations, due to their abundance and dominance in tropical forest soils (Verma et al., 2009).
Coptotermes workers penetrate the plants by the roots and then build tunnels in the heartwood along the trunk of the tree (Evans et al., 2019). However, the termites male and female alates during the flight period can also penetrate the tree due to pre-existing damage to the trunk (eg. Pruning activity) and establish new nests (Greaves, 1962). Some species of this genus leave external signs (tube or extend carton material) of their presence in the tree (Scheffrahn et al., 2015), while others are detected only during the harvest or because the damaged tree naturally falls (Moraes et al., 2002). Several other trees surrounding a nest can also be attacked, when an attacked tree is found, the chance of finding other attacked trees in a near location is high (Tho and Kirton, 1998). The galleries of a colony of this termite can extend over an area of 0.16 ha, with galleries reaching up to 47.54m in length, and the same nest can attack 5 trees (Greaves, 1962).
Coptotermes testaceus is the most important species of heartwood termite in adult trees in forests planted in Brazil (Lukmandaru, 2015), mainly in eucalyptus (Moraes et al., 2002;Calderon and Constantino, 2007). However, it was recorded, causing damage to rubber trees, coconut palms, and other palm trees, citrus, and other fruit trees and cassava (Mill, 1992;Apolinário and Martius, 2004).
C. testaceus lodges in young plants (2-3-years) and feeds on the heartwood (Constantino, 2002). Commonly the infestation is only detected during the harvest, as was detected in eucalyptus plantations in the Cerrado ecoregion, with worldwide wood losses production around 3.76 m³ . ha -1 (Santos et al., 1990). There is no record of C. testaceus damage in T. grandis plants.
This study aimed to characterize the damage caused by the heartwood termite C. testaceus (Blattodea: Termitidae: Rhinotermitidae) in clonal plantations of Tectona grandis L. f. (Lamiaceae). The 7.2-year-old trees presented a mean of 36 cm of total diameter and 23 cm of heartwood, while the trees of 4.2-year of age had, on average 25 cm of total diameter and 9 cm of heartwood, at a height 10 cm from ground level.

Trees
Samples of infested trees with termites were taken to the laboratory, where transverse and longitudinal cuts with a chainsaw were made, and the injuries were photographed and characterized. The termites soldiers were collected with tweezers and placed in vials containing 80% alcohol was transported to the laboratory, examined, and photographed with a stereoscopic microscopy (40x) and sent to Dr. Tiago Fernandes Carrijo in Universidade Federal do ABC, São Bernardo do Campo, State of São Paulo, Brazil, for species identification.

RESULTS
The collected termites were identified as C. testaceus (L., 1758). The infested trees were detected by the external galleries on the stem (Figure 1), characterized by a layer of feces and soil covering (carton material) the galleries that lead to the nest inside the tree. COSTA, et al. Internal damages promoted by termites were characterized by galleries along the entire heartwood stem length and by some soil, carton material and termite feces inside the galleries (Figure 2).

DISCUSSION
Damage by C. testaceus on eucalyptus plants did not show in external stem signs, and the infestation was only noticed during the trees harvest (Santos et al., 1990). Coptotermes genus begin their nests in living trees (Cowie et al., 1989), being C. testaceus, the main species of nidification of live trees in the Amazon (Apolinário and Martius, 2004). This species is distributed throughout the Neotropical region, which can be explained by the high availability of food resources and favorable environmental conditions (Scheffrahn et al., 2015).
The control of Coptotermes spp. it is carried out by soil drenching around the tree (Tho and Kirton, 1992). In Brazil, there is no technical recommendation for the control of Coptotermes genus in forests planted with teak, however, in adult eucalyptus plantations, fipronil (phenyl-pyrasol) was used, distributed 0.30m around the trunk, and the 0.1g dose of fipronil per plant did not cause phytotoxicity the plants and protected from the attack of termites Heterotermes tenuis (Hagen, 1858) and Cornitermes sp. Wasmann 1897 for up to a year (Raetano et al., 1997). Since 2019, the fipronil was approved as a termiticide for teak in Brazil (MAPA, 2019), but studies for recommendation control for this insect species in teak forests must be conducted.

CONCLUSION
Occurrence and damage characterization of C. testaceus termites in clonal plantations of Tectona grandis, in different ages and regions in Brazil are reported.