Mortality

In both plantations, drought and gophers were the main factors that caused the largest plant mortality percentages. The symptoms of death by drought were curling of the leaflets, followed by withering and death of young leaves and, subsequently, by downward withering and death of the adult leaves and stem; the roots exhibited no damage due to predation. The individuals killed by gophers exhibited gnawed roots and the presence of gopher tunnel entrances at the base of the plant stems. The identified species was Orthogeomys grandis (Thomas, 1893), which is widely distributed in the Coast of Oaxaca (^{Lira et al., 2005}). Total mortality rates increased during the evaluation period (Figure 2), and there were significant differences between sites (p= 0.03312); mortality due to drought (p˂ 0.0001) and to gophers (p˂ 0.0001) also increased. In both Pinotepa de Don Luis and Valdeflores, the total mortality rate was 38.3 and 45.8 %; mortality due to drought was 8.3 and 29.2 %, and mortality due to gophers, 27.9 y 0.4 %, respectively (Figure 2).

Mortalidad acumulada = Accumulated mortality; Meses después de la plantación = Months after planting.

Figure 2 Mortality (total, due to droughts and to gophers) of Enterolobium cyclocarpum (Jacq.) Griseb. accumulated in three periods (6, 12 and 18 months) in Pinotepa de Don Luis (A) and Valdeflores (B), in the Coast of Oaxaca region. 

The mortality factors were differentiated between plantation sites: drought was the main cause of mortality in Valdeflores, and attack by gophers, in Pinotepa de Don Luis. The difference in mortality rates due to drought between the sites was rain-related: the mean annual precipitation in Valdeflores (910 mm) was lower than that registered in Pinotepa de Don Luis (1 645 mm), while the aridity index (AI) in Valdeflores (8.2) was higher than that of Pinotepa de Don Luis (4.6). In the latter locality, predation by gophers was greater, due, perhaps, to the fact that, during the first six months, the plantation was mixed with corn crops, which may have induced a greater damage because corn is food for the gophers. ^{Viveros-Viveros et al. (2005)} cited mortality caused by gophers in a Pinus pseudostrobus Lindl. assay in which the population of this rodent increased in response to the agricultural history of the site, the availability of food, and the elimination of its natural predators. Furthermore, the soils of Pinotepa de Don Luis are silty and deep, which facilitates the digging of burrows by this mammal; on the other hand, in Valdeflores the soil is clayey and shallow (^{INEGI, 2013}).

The total mortality was significantly different (p≤ 0.0355) between provenances at both sites. In Pinotepa de Don Luis, the plants from the San Pedro provenance had a lower total mortality and those from Colotepec had the highest; likewise, the plants from San Pedro and Pochutla were less affected by the gophers, and those from Cortijo were most affected. On the other hand, individuals from four provenances showed more tolerance to drought (Table 2). In Valdeflores, plants from the Cortijo and Tataltepec provenances had a lower total mortality and exhibited a higher tolerance to drought, unlike those of San Francisco, which had the highest total mortality rate and less tolerance to drought (Table 2).

In Pinotepa de Don Luis, the plants produced with seeds from the same locality evidenced a higher tolerance to drought, which proved that the local provenance is better adapted. However, the specimens from San Pedro were tolerant to drought and to predation by gophers. This response may be due to the fact that it is one of the provenances with a similar altitude to that of the plantation site and a high AI (6.8); thus, it is a better location for planting than Pinotepa de Don Luis, which is more humid (AI= 4.6). In Valdeflores, the Colotepec provenance was the closest to the plantation site and had the same AI as this (8.2); therefore, it was expected to have the lowest plant mortality rate. Nevertheless, it exhibited an intermediate value, which is statistically equal to all the provenances. The result for Colotepec in Valdeflores may have been due to the difference in the soil type, which is Cambisol in Colotepec and Phaeozem at the site of establishment (^{Inegi, 2013}).

Health

Six biotic agents related to the health of E. cyclocarpum were identified (Table 3, figures 3 and 4) during the assessment period; of these, powdery mildew of the genus Oidium Link and aphids (Aphis L.) were more prevalent on the assay plants. In Mexico, there are few records of attack by powdery mildew in forest species, particularly in tropical ones. Robles (2010) refers to cases of infection by Oidium sp. in nursery-grown E. cyclocarpum saplings. ^{García and Cibrián (2007)} cite infections in nursery-grown Acacia spp., Erythrina spp. and Quercus spp. saplings, while ^{Cibrián et al. (2007b)} document infection by powdery mildew (Podosphara Kunze, Micrisphaera Lév. and Phyllactina Lév.) in adult Acacia spp., Fraxinus spp., Quercus spp., Ulmus spp., Acer negundo L., Erythrina coralloides DC. and Platanus occidentalis L. plants.

Figure 3 Powdery mildew of the genus Oidium (A) and its effect (B), aphids of the Aphis genus (C) and Pseudoccocus longispinus (Targioni Tozzetti, 1867) (D) in provenances of Enterolobium cyclocarpum (Jacq.) Griseb. in the Coast of Oaxaca. 

Figure 4 Longhorn beetle of the genus Oncideres (A), larva of the stem bark beetle (C) and larva of the defoliator insect (E), and their respective damages (B, D, F) in Enterolobium cyclocarpum (Jacq.) Griseb. provenances of the Coast of Oaxaca. 

In Mexico, aphids of the genus Aphis damage the rachis of the leaves and tender stems of nursery-grown E. cyclocarpum saplings and adult plants (^{Solares, 2008}; Robles, 2010); in Venezuela, Aphis spiraecola Pach affects adult plants of the same species (^{Evelin and Marcos-García, 2004}). In Mexico City and in the State of Mexico, Aphis nerii Boyer de Fonscolombe aphids damage Nerium oleander L. leaves (^{Cibrián et al., 1995}). In other countries, like Costa Rica, Cuba, Colombia and Venezuela, Aphis sp. attacks Eucalyptus deglupta Blume (^{Arguedas, 2008}), A. gossypii Glover affects Tectona grandis L. Fil, A. spiraecola Patch damages Cordia alliodora (Ruiz & Pav.) (^{Cibrián, 2013}), and A. craccivora Coch affects Gliricidia sepium (Jacq.) Steud and Cordia alba (Jacq.) Roem & Schult (^{Evelin and Marcos-García, 2004}).

The occurrence of Oidium sp. and Aphis sp. was significantly different between sites (p˂ 0.0001). In Pinotepa de Don Luis, an average of 58.8 % and 29.2 % of the plants exhibited infection by Oidium and Aphis, respectively, while in Valdeflores the average percentages were 3.3 % and 0.8 %. This may be due to the difference in location and precipitation of the sites. Pinotepa de Don Luis is located at a higher altitude, and there is a greater precipitation in this site than in Valdeflores (Table 1). Accordingly, the risk of attack by Oidium mangiferae Berthet increases with the altitude of the sites (^{Arias et al., 2004}). Furthermore, infection by the fungus Cercospora coffeicola Berk & Cooke is related to high precipitation (^{Montes et al., 2012}).

In each of the plantations, the incidence of Oidium sp. was significantly different between provenances (p≤ 0.0389). In Pinotepa de Don Luis, the Cortijo and Colotepec provenances had a lower percentage of plants infected by Oidium sp. (41.7 %); conversely, Los Limones registered a higher percentage of infection (70.8 %) (Table 3). In Valdeflores, the Cortijo, El Zarzal, La Tuza, Tataltepec and San Francisco provenances exhibited infection (4.2 to 8.3 %), while the others had none. Since the provenances Cortijo, El Zarzal and La Tuza showed lower percentages of infection by Oidium sp. in Pinotepa de Don Luis, no infection was expected to be found in Valdeflores; however, the opposite was the case, due to the genotype x environment interaction (p= 0.049) in the occurrence of Oidium sp. on E. cyclocarpum.

As for the occurrence of Aphis, there were no significant differences between the provenances in Pinotepa de Don Luis (p= 0.0603); conversely, such differences were found in Valdeflores (p= 0.0012), but the effect of the genotype X environment interaction was not significant (p= 0.5300). In Pinotepa de Don Luis, infection by Aphis varied from 16.7 to 41.7 % between provenances. However, in Valdeflores only 8.3 % of the plants of El Zarzal exhibited infection (Table 4).

The difference between the occurrence of Oidium sp. and that of Aphis sp. in E. cyclocarpum allows selecting of adequate provenances for each plantation site. However, the existence of the genotype x environment interaction in young plants hinders their early selection for various sites. Nevertheless, the instability of certain characteristics in different environments is usual in trees or in wild provenances (^{Salaya-Domínguez et al., 2012}). On the other hand, subsequent assessments are required, as the effect of the interaction may vary according to age (^{Salaya-Domínguez et al., 2012}).

During the study period, powdery mildew affected only three plants in Pinotepa de Don Luis. In Mexico, these insects are documented to affect the leaves and stems of adult E. cyclocarpum trees, causing yellowing, reduced growth, and branch death (^{Solares, 2008}). Likewise, the pink mealy bug (Maconellicoccus hirsutus (Green)) also causes malformation in E. cyclocarpum shoots, leaves, branches and fruits (^{López-Arriaga et al., 2010}; ^{Sinavef, 2011}; ^{Isiordia-Aquino et al., 2012}). There are no records of attack by powdery mildew in other forest species; only the pink mealy bug has been documented in Tectona grandis, Artocarpus hererophyllus Lam. and Acacia spp. (^{Sinavef, 2011}).

In Mexico, 20 species of the Oncideres Lacordaire genus have been registered (^{Monné and Bezark, 2011}), which are in the habit of forming rings around adult tree branches or trunks of young specimens in order to deposit their eggs (^{Villaverde and Acosta, 2013}), as was observed in one and three E. cyclocarpum plants in Valdeflores and Pinotepa de Don Luis, respectively. Although the presence of Oncideres species, which no attack of E. cyclocarpum was observed in Huatulco (in the Coast of Oaxaca region), the occurrence of Oncideres pallifasciata Noguera (^{Noguera et al., 2018}) has been registered at a linear distance of 108 and 57 km from Pinotepa de Don Luis and Valdeflores, respectively. However, there is no documentary evidence of infestation by Oncideres spp. in E. cyclocarpum plants; therefore, this study is the first record of its occurrence. Notably, in Costa Rica, Oncideres punctata Dillon & Dillon causes the same damage in E. cyclocarpum trunks (^{Hilje and Arguedas, 1996}).

The presence of Oncideres ocellaris Bates, O. scitula Bates; O. senilis Bates and O. albomarginata chamela (^{Noguera, 1993}; ^{Toledo et al., 2007}; ^{MacRae et al., 2012}; ^{Nearns et al., 2014}) is cited in Oaxaca, Mexico. The third of these species affects Amphipterygium adstringens Schide ex Schlecht, Bursera Jacq. ex L. spp. y Ceiba pentandra (L.) Gaertn trees (^{Calderón-Cortés et al., 2011}). In Tamaulipas, Mexico, O. pustulata LeConte is hosted by Acacia farnesiana (L.) Willd. and Leucaena leucocephala (Lam.) de Wit plants (^{Rodríguez-del-Bosque and Garza-Cedillo, 2008}; ^{Rodríguez-del-Bosque, 2013}). In the Desert of Chihuahua, Mexico, O. rhodosticta attacks Prosopis glandulosa var. torreyana (L. Benson) M.C. Johnston (^{Martínez et al., 2009}), while, in Nuevo León and Tamaulipas, Mexico, O. cingulata texana Horn and O. pustulatus infest specimens of Acacia farnesiana (L.) Willd., Acacia spp., Citrus spp., Leucaena spp., Pithecellobium spp. and Prosopis spp. (^{Cibrián et al., 1995}).

The stem bark beetle of E. cyclocarpum (Lepidoptera) affected 22 plants in Pinotepa de Don Luis, and five in Valdeflores. Although this species was not identified due to a lack of adult specimens, this is the first record of damage by a bark beetle in young E. cyclocarpum plants in Mexico. On the other hand, an unidentified bark beetle that bores superficial galleries in the stems and another one that bores numerous galleries damaging the vascular cambium, the xylem and the phloem (^{Solares, 2008}) were observed in adult trees. Xyleborus volvulus (F.) (Coleoptera) forms galleries at various levels of the tree trunk (^{Cibrián et al., 1995}). The damage caused by X. volvulus (^{Cibrián et al., 1995}) and by the bark beetles mentioned by ^{Solares (2018)} do not correspond with the damage observed in the present study, in which the main shoot is the affected part (Table 3, Figure 4C and 4D).

At both plantation sites, a defoliator insect of the Lepidoptera order was observed in four E. cyclocarpum plants. In Mexico, there are no records of defoliator insects in E. cyclocarpum; therefor, the present study is the first record of the present of these insects; however, more studies are required in order to be able to identify the species, its life cycle, and its effect on E. cyclocarpum plants. Coenipita bibitrix Huebner (Noctunidae), Mocis latipes Guenée (Noctunidae), Hylesia lineata (Saturniidae), and an unidentified species of the family Meloidae are known to defoliate E. cyclocarpum plants in Costa Rica (^{Janzen, 1981}; ^{Arguedas, 2008}).