Moringa oleifera Lam. and Ricinus communis L. are important oleaginous species with many industrial applications. Both of them were introduced to Mexico during the colonial era (^{BDMTM, 2009}; ^{Olson and Fahey, 2011}); however, studies of their cultivation only began after the 1960s and to date, very few aspects regarding their possible pests have been documented in the country (^{Pérez et al., 2010}; ^{Rico et al., 2011}). In the central region of Veracruz, none of these crops have been established for commercial purposes, although naturalized plants of R. communis are commonly found growing on abandoned plots or along the edge of roads, while M. oleifera has not been reported as naturalized in any part of the country. The climate in this region is hot and humid, hosting a diversity of herbivorous insects that can attack new crops. Information about performance of these crop species would therefore be of great value to potential producers.

An experimental plot with R. communis and M. oleifera was established in the Colegio de Postgraduados research center, located in the central region of the state of Veracruz. Initial results published by ^{Valdés et al. (2014)} briefly identified important insect pests that affected both species. The aim of this study is to document: 1) the behavior of the main insect pests affecting cultivars of M. oleifera and R. communis in relation with the climatic conditions and; 2) the effect of these insects on the survival and productivity of these plants.

R. communis seeds were obtained from a private collection on the Mexican plateau in San Luis Potosi state; the plants belong to a red variety with a seed weight of 478.8±29.0 mg (average ± standard deviation). M. oleifera seeds were obtained from a commercial plantation in the state of Morelos, with a seed weight of 268.9 ± 42.9 mg. The experimental plot was established in the Colegio de Postgraduados research center, located in the Municipality of Manlio Fabio Altamirano, in Veracruz state, Mexico (19° 16' 00" N, 96° 16' 32" W; 16 masl). The plantation was established in late September 2012 on a clay-loam Argiudoll soil (^{Ortiz and López, 2000}). Following soil preparation, seeds were sown in the field in intercropped rows of M. oleifera and R.communis at distances of 2 m between plants and 6 m between rows. At the beginning of May 2013, additional intercropped rows of R. communis and M. oleifera were added at distances of 2 m (between plants) and 3 m (between rows), reaching a total of 12 rows with 148 plants of each species. Plants were not irrigated and monthly weeding of the plot was conducted only during the rainy season (June to August). Plants were monitored daily over the first two weeks after sowing and weekly thereafter. The insects feeding on the plants were sampled and plant damage recorded over a period of two years (2012-2014). The insects were conserved in alcohol (70%) and send to the phytosanitary department of the Colegio de Postgraduados for identification by entomologists, consulting both the local collection and reference materials. Commercial insecticides were applied to control the pests during the first year only, recording the outcomes. In addition, climatic measurements (temperature, rainfall and environmental humidity) were taken from the local meteorological station in order to identify associations between insect presence and climatic conditions.

The climatic conditions of the site are shown in Figure 1A. Environmental humidity during the two -year period was always greater than 75% and the average temperature was 25 °C. The temperatures in the study area are within the recommended ranges for both crops (^{Parrota, 2009}; ^{Nielsen et al., 2011}); however, the environmental humidity is excessive for R. communis, which is affected by pests and mold when exposed to humidity over 60% (Nielsen et al., 2011). The major insect pests found on R. communis and M. oleifera are shown in Table 1.

Figure 1 A) Climatic conditions during the monitoring period; and B) Average number of insects observed and plant productivity during the monitoring period. 

Table 1 Pests and damage observed on intercropped Ricinus communis and Moringa oleifera in central Veracruz, Mexico. 

Main insect pests found on M. oleifera. The caterpillar identified as Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) was observed only during the seedling stage of M. oleifera , although it should be noted that one individual was able to consume up to three seedlings per day. However, only four individuals were found on the M. oleifera seedlings sown in September 2012. These insects could be removed manually, thus avoiding the use of any insecticide.

The incidence of the leafcutter ant Atta mexicana (Smith) (Hymenoptera: Formicidae) was noted, with a rate of defoliation of four seedlings of average height 1.5 m per night. A commercial insecticide (Foley), consisting of a powder containing parathion-methyl (2%), was effective against the ants, but it was washed away by the rain and had to be reapplied periodically during the rainy season until the ant nest was located and eliminated. No attacks were observed in adult M. oleifera trees, although ants were observed months later in other parts of the zone.

The presence of T. ni could be associated to the raining season, because none of them were observed during the dry season, while A. mexicana was observed during the whole year, therefore the presence of this insect was not associated to climatic variations. Both T. ni and A. mexicana were reported as insect pests of M. oleifera while in the nursery stage in the state of Sinaloa (^{Pérez et al., 2010}), where the climate is warm sub-humid. However, no other relevant documentary information is currently available. A similar preference of A. mexicana for young plants was documented for Hibiscus sabdariffa L. in the state of Puebla (^{Pérez-Torres et al., 2009}) and it is possible that leaf cutter ants prefer seedlings because their leaves have lower amounts of cellulose and are easier to cut (^{Olson, 2014}). Since none of these insects were observed during the productivity stage, their effects on production were not quantified. Although T. ni and A. mexicana were only a threat for M. oleifera during seedling stage, it should be considered that plants might require daily supervision during this period, when they could be protected by a greenhouse mesh to avoid the use of insecticides.

Main insect pests found on R . communis. Just after the beginning of the rainy season, Sagotylus confluens (Say) (Hemiptera: Coreidae) were observed in 100% of the R. communis plants in the plot and mortality was 13% one month after the first appearance, increasing to 25% by the second month, when these insects were eliminated by spraying with the commercial insecticide Carex (Cypermethrin 21.46%) diluted to 2% with tap water. To prevent further attacks and avoid pesticides, the plants were sprayed with a biodetergent named Vel Rosita^® at 5% (formulates unavailable), containing anionic and nonionic surfactants, optical brighteners, preservatives, opacifiers, colorants and perfumes, but it has no phosphate.

Starting the dry season, initially tens and subsequently hundreds of the lace insect Corythucha gossypii (Fabricius) (Hemiptera: Tingidae) were observed on R. communis. These insects were present throughout the entire year and their number decreased only slightly during the rainy season. C. gossypii was not affected by Vel Rosita^® detergent, being eliminated only by the application of insecticide (Carex). In the absence of any measure of pest control after a period of five months, 50% of the plants died and seed productivity decreased by up to 90% (Figure 1B).

S. confluens is native to Mexico and the United States (^{ITIS, 2014}) and may constitute a major threat to R. communis given the large size of both individuals and populations of this species (Figure 1B and 2C). This pest can be easily eliminated with a commercial biodetergent (Vel Rosita^®), which has to be applied only during the raining season, when the insect is present on the plants. However, we did not find any local method to control C. gossypii. This lace insect was also found in naturalized and experimental plantations of R. communis in the state of Chiapas, but to date no economic assessment has been published (^{Solís et al., 2011}). Records from Florida state in the USA (^{Mead, 1989}) indicate that the favorite host of C. gossypii is R. communis, while studies in Colombia found that high infestations of this insect cause a loss of up to 73 leaves per plant after a period of two weeks (^{Varon et al., 2010}).

Figure 2 Major insect pests observed in intercropped Moringa and Ricinus and associated damage A) Atta Mexicana; B) Corythucha gossypii; and C) Sagotylus confluens 

These authors also found that only highly a toxic insecticide (based on imidacloprid) could reduce but not eliminate this pest. C. gossypii was observed in naturalized R. communis plants in nearby areas, but only a maximum of two insects by leaf were counted. It is important to note that plants in nearby areas are green varieties with small seeds, while our red variety with bigger seeds may lack the protection that the local plants seem to have developed. Therefore, a breeding program should be implemented to combine local pest’s resistance with high seed productivity if R. communis is to be considered a commercial option for local producers.