Pastos y Forrajes, Vol. 43, No. 1, 70-78, 2020 70 Osmel Alonso-Amaro Potential insect pests of Leucaena leucocephala (Lam.) de Wit in the seed production stage in Cuba Osmel Alonso-Amaro1 https://orcid.org/0000-0003-1078-0605, Rayner Núñez-Águila2 https://orcid.org/0000-0002-4584-8510, Vicente Horacio Grillo-Ravelo3 https://orcid.org/0000-0002-1373-050X, Juan Carlos Lezcano-Fleires1 https://orcid.org/0000-0002-8718-1523 y Moraima Suris-Campos4 https://orcid.org/0000-0002-7032-8250 1Estación Experimental de Pastos y Forrajes Indio Hatuey, Universidad de Matanzas, Ministerio de Educación Superior. Central España Republicana, CP 44280, Matanzas, Cuba. 2Instituto de Ecología y Sistemática. Carretera de Varona, km 3.5. Capdevila, Rancho Boyeros, La Habana, Cuba. 3Centro de Investigaciones Agropecuarias, Universidad Central Marta Abreu de Las Villas. Carretera a Camajuaní, km 5 y ½. Santa Clara. Villa Clara, Cuba. 4Centro Nacional de Sanidad Agropecuaria. Autopista Nacional y Carretera de Tapaste, San José de las Scientific Paper Scientific Lajas, C.P. 11300, Mayabeque, Cuba. E-mail: [email protected] Abstract Objective: To define the potentiality of two phytophagous insects to become pests of Leucaena leucocephala (Lam.) de Wit during its reproductive phenophase, in Cuba. Materials and Methods: Two productive systems with Leucaena leucocephala (Lam.) de Wit cv. Peru and Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs cv. Likoni were evaluated. The characterization of the lesions produced by the insect on the inflorescences was carried out during one year. Meanwhile, the characterization of the insect lesions on the pods and seeds, and that of the associated bacterial symptoms, took place during three years. The link between insect and symptoms in those organs was determined with a regression analysis through the program SPSS®. The relation between number of insects and pods and seeds infected by the bacterium per season was conducted for two years, and it was tested by a proportion comparison test. To evaluate the proportion between the quantity of insects and infested organs, a regression was made; while the estimation of the losses caused by both insects was through rule of three. Results: The micromoth found on the inflorescences wasIthome lassula, which affected more during the dry season. The organisms found in the pods and seeds were the insect Loxa viridis, and the bacterium Pectobacterium caroto- vorum subsp. odoriferum, which had a close relation with the reproductive phenophase of L. leucocephala. These organisms also have higher presence in the dry season. Conclusions: Associated to the reproductive organs of L. leucocephala, the micromoth I. lassula, due to its direct affectation on the inflorescence, and the pentatomid L. viridis on the pods and seeds, were detected with potentiality to become pests. Keywords: Leucaena leucocephala, inflorescences, pods, seeds, potential pests Introduction systems also stands out, as alternative to systems Leucaena leucocephala (Lam.) de Wit is one with grasses exclusively, in order to reduce green- of the most important exotic plant species in animal house gas emissions, specifically of CH4, which is husbandry agroecosystems in the region of Latin originated in the ruminal fermentation of digestible America and the Caribbean, because it is a plant that fiber (Molina et al., 2016; Morales-Velasco et al., should be considered against soil erosion, degrada- 2016). It has been proven that with the systems with tion and compaction and the subsequent loss of the trees the productive increase of the animals and of productive capacity of the land. Hence it is considered the environmental services that are generated in the an essential plan t resource for recovering the sta- ecosystem, is achieved (Chará et al., 2019). bility, fertility and agricultural potential of the land Another one of the most outstanding attributes of (Calle et al., 2011). It is also a multipurpose tree, L. leucocephala is that this forage is capable of pro- -1 which contributes green manure to the soil, and from ducing up to 1 t or more of total seed (TS) ha . Spe- which timber is obtained Brewbaker et al., 2016. cifically, cultivar Peru produces between 450 and 610 -1 In sustainable tropical animal husbandry, its use kg of TS ha without pruning; while when pruning in cattle constitutes a challenge to produce profitably is performed in June, every two years, it can produce -1 in an environment of conservation of natural resources, from 315 to 588 kg TS ha (Milera y Sánchez, 2017). where diverse organisms coexist in healthy ecosys- However, its seed production is affected by different tems (Cortez-Egremy et al., 2016; Murgueitio-Re- phytophagous insects and pathogens, which prevent it strepo et al., 2016). Its inclusion in silvopastoral from reaching these yields (Ahmed et al., 2016). Received: January 06, 2020 Accepted: March 20, 2020 How to cite a paper: Alonso-Amaro, O.; Núñez-Águila, R.; Grillo-Ravelo, V. H.; Lezcano-Fleires, J.C. & Suris-Campos, Moraima. Insectos plagas potenciales de Leucaena leucocephala (Lam.) de Wit en la fase de producción de semillas en Cuba. Pastos y Forrajes. 43:70-78, 2020. This is an open access article distributed in Attribution NonCommercial 4.0 International (CC BY-NC4.0) https://creativecommons.org/licenses/by-nc/4.0/ The use, distribution or reproduction is allowed citing the original source and authors. Pastos y Forrajes, Vol. 43, No. 1, 70-78, 2020 Potential insect pests of L. leucocephala in the seed production stage in Cuba 71 In this group of insects, those belonging to the It was performed at the sampling spots formed by orders Lepidoptera and Hemiptera, of the fami- one or two trees, depending on the quantity of flow- lies Cosmopterigidae and Pentatomidae, in each ers they had. case, stand out, which affect the inflorescences and Of the climate elements, the accumulated rain- pods, respectively. The insects of the family Cos- fall in both months was recorded: 19,1 mm in April mopterigidae are included in the more than 130 and 112 mm in August. The data were from the me- species that existed in the neotropical region, ac- teorological station Indio Hatuey. cording to reports of a review by Landry (2001). At each sampling time, in the four cardinal Those of the family Pentatomidae, just like the points of the plant, five buds and five inflorescences former, are considered phytophagous pests, of high with peduncle were taken. The samples were placed economic importance in the forage legumes of that separately in the transparent nylon bags. They were region (Panizzi and Grazia, 2015; Grazia et al., closed with an elasticized string to prevent the es- 2015). The objective of this work was to define the cape of the insects in the transference from the ex- potentiality of two phytophagous insects to become perimental field to the plant protection laboratory pests of L. leucocephala, during its reproductive of the EEPFIH. phenophase, in Cuba. In the laboratory, with a Zeiss stereoscopic mi- Materials and Methods croscope, the 100 inflorescences and the 100 buds of each sampling moment were observed, in order Location of the experimental areas. The exper- to count the number of eggs, larvae, pupae and imental areas were established at the Pastures and adults of the insect. From the total sample of in- Forages Research Station Indio Hatuey (EEPFIH), florescences, 30 with visible affectations were ran- located in Matanzas province, in the western region domly taken, to quantify, describe the lesions, and of Cuba. determine the number of eggs, larvae, pupae and Evaluated experimental areas and their main adults of the insect per individual flower, as well as characteristics. A silvopastoral system (SPS) (pad- the quantity of damaged flowers. dock) was evaluated, aimed at bull fattening and Procedure for characterizing the lesions of established with the association of the commercial the phytophagous insect associated with the pods varieties L. leucocephala cv. Peru (leucaena) and and seeds, and their relation to a bacterial disease. Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. During three years, in the SPS, 5 % of the L. leuco- Jacobs cv. Likoni (Guinea grass likoni), approved in cephala cv. Peru plants were evaluated, in order to Cuba by MINAG (2017). In addition, another sys- collect pods with green, forming and mature seeds tem was studied, with similar species composition, (at the moment of their emergence in each case) as but aimed at beef and seed production (SPSDP). well as the insects present. The collection was car- They were both located on a lixiviated ferralitic red ried out every fifteen days, for which nylon bags soil Hernández-Jiménez et al., 2015, with1,3 ha of were used. The insects and the lesions they caused surface and density of 396 trees ha-1 (516 trees in per pod were quantified. In addition, such lesions each area) and six years of exploitation. were described. Main elements of phytosanitary management. The bacterial symptoms present in the collect- No inorganic or organic fertilization, irrigation or ed pods, associated with the lesions produced by chemical or biological pesticides were applied. the insects, were quantified and described, in order Method for insect sampling (collection). The to corroborate the reports in studies conducted by transparent nylon bag was used. Delgado et al. (1989) and Alonso et al. (1993). In Method for insect evaluation. The method of the addition, the number of seeds infected by the bacte- envelope in five spots of the paddock was applied. rium was counted. Afterwards, the bacterial species Procedure for characterizing the lesions of the was isolated and identified in the plant bacteriolo- phytophagous insect associated to inflorescences. gy laboratory of the National Agricultural Health In the SPS, during one year, in the full flowering Center (CENSA, for its initials in Spanish) through stage (more than 70 % of the plantation flowered), morphological, physiological and biochemical tests.