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ABSTRACT The study was conducted throughout two seasons (2013 and 2014) at Xmatkuil farm at Merida, Yucatan, Mexico to study the effects of the natural enemies on the population dynamics of Leucaena leucocephala (Lam.) de Wit pests: Leucaena Psyllids, Heteropsylla cubana Crawford, 1914 (Homoptera: Psyllidae) and Onion Thrips, Thrips tabaci Lindeman, 1889 (Thysanoptera: Thripidae) on four Leucaena genotypes: Cunningham, K636, Nativa and KX2. The Juvenile leaves were collected, examined and the natural enemy’s counts were correlated with each pest numbers. Nine predators related to 5 Orders, and one parasitoid controlled the populations of both pests. In the first season Nativa had the largest densities of Psyllid, and Cunningham for Thrips. In the second season, Nativa for both pests. The least numbers recorded in KX2 for both pests. The coefficient of correlation (r) was stronger between natural enemies and H. cubana than T. tabaci. In the first season three peaks of Psyllid were occurred, two before the first harvest during May and June and one after at December. Otherwise, four peaks of Thrips were recorded on Cunningham, Nativa, and K636 during May to Aug. and only two occurred on KX2 at May and June. In the second season the largest population of pests was recorded in Nativa, and the lowest were in KX2 for both pests. (r) was negative between Thrips and natural enemies. Psyllid showed two peaks in February and April, and two for Thrips in April and June. Survey the natural enemies of Leucaena Psyllid and Onion Thrips, and study their effects with harvest processes on the population fluctuation of both pests on different Leucaena genotypes. Resumen El estudio se llevó a cabo en 2013 y 2014, en Xmatkuil, Mérida, Yucatán, México a la encuesta enemigos naturales y sus efectos sobre la dinámica poblacional de Leucaena leucocephala (Lam.) de plagas Wit: Leucaena Psílidos, Heteropsylla cubana Crawford (1914) (Homoptera: Psyllidae) y cebolla trips, Thrips tabaci Lindeman, 1889 (Thysanoptera: Thripidae) en cuatro genotipos de Leucaena: Cunningham, K636, Nativa y KX2. Se recogieron las hojas juveniles, examinaron y cuenta del enemigo natural, se correlacionaron con cada uno de los números de plagas. Nueve depredadores relacionados con 5 órdenes, y uno parasitoide controlan las poblaciones de ambas plagas. En la primera temporada Nativa tuvo las mayores densidades de Psyllid, y Cunningham para Thrips. En la segunda temporada, Nativa para ambas plagas. Los números de menos registran en KX2 para ambas plagas. El coeficiente de correlación (r) fue más fuerte entre los enemigos naturales y H. cubana que T. tabaci. En la primera temporada se produjeron tres picos del psílido, dos antes de la primera cosecha en mayo y junio y una después en diciembre. De lo contrario, cuatro picos de trips se registraron en Cunningham, Nativa y K636 durante mayo a agosto y sólo dos ocurrieron en KX2 en mayo y junio. En la segunda temporada de la mayor población de plagas se registró en Nativa, y la más baja se encontraban en KX2 para ambas plagas (r) fue negativa entre trips y enemigos naturales. Psyllid mostró dos picos en febrero y abril, y dos para los trips en abril y junio.

Abstract The study was conducted throughout two seasons (2013 and 2014) at Xmatkuil farm at Merida, Yucatan, Mexico, to determine the relationships and the interactions between chemical compositions of condensed tannins and mimosine and their effects on the susceptibility of four Leucaena genotypes: Cunningham and K636 (L. leucocephala), and Nativa and KX2 (L. leucocephala 9 L. pallida) to the infestation of the most destructive insect pests; Leucaena Psyllids, Heteropsylla cubana Crawford, 1914 (Homoptera: Psyllidae), and Onion thrips, Thrips tabaci Lindeman, 1889 (Thysanoptera: Thripidae). Mimosine showed insignificant effect on the population of both pests. However, tannins exhibited a significant effect for Psyllid population on Nativa and K636, and highly significant effect on thrips for the same respective genotypes. The insignificant relationships of tannin effect were found for Cunningham and KX2 to the population fluctuations of Psyllid and Thrips.

SUMMARY The present review was written with the objectives of providing basic information for pest control about leucaena psyllid, Heteropsylla cubana Crawford (Homoptera: Psyllidae) the most destructive insect pest of Leucaena sp. In the regard of pest control, the review focus on discussing the findings of the existing researches about the factors affecting the distribution and seasonal fluctuations of H. cubana in the world. These factors are biotic such: biological control agents, and abiotic such: climatic factors, leaves chemical composition and genetic control which significantly affect pest population. A basic understanding of the relationship of these factors with psyllid population is important in developing an integrated control strategy for psyllid in leucaena and determining the potential pest control needs under the given biotic and abiotic factors trend. Besides, develop some concepts of pest control which effect directly and indirectly on the survival and population dynamics of H. cubana around the world. RESUMEN La presente revisión fue escrita con el objetivo de proporcionar información básica para el control del psílido Heteropsylla cubana Crawford (Homoptera: Psyllidae). Una de las plagas más destructivas de Leucaena sp. La revisión se centra en la discusión de los resultados de investigaciones existentes sobre los factores que afectan la distribución y las fluctuaciones estacionales de H. cubana en el mundo. Estos factores son, tanto bióticos, tales como: agentes de control biológico y abióticos como: factores climáticos, composición química de las hojas y el control genético el cual puede afectar significativamente la población de plagas. Un conocimiento básico de la relación de estos factores con la población del psílido es importante para el desarrollo de una estrategia de control integrado del psílido en leucaena y determinar el potencial necesario para el control de plagas considerando los factores bióticos y abióticos. Además, el desarrollo de algunos conceptos de control de plagas que afectan directa e indirectamente en la dinámica de supervivencia y de población de H. cubana en todo el mundo.

Abstract The aim of this study was to evaluate the effect of the intake of leucaena, Enterolobium cyclocarpum, fruits and a mixture of both feeds on in vitro gas production and in vivo sheep productive performance. The experiment was conducted at the University of Yucatan, Mexico. Twenty-four Pelibuey sheep, 20.28 ± 2.99 kg average liveweight (LW), were used. Animals were randomly assigned to the following experimental treatments: T1: 100% Pennisetum purpureum, T2: 30% Leucaena leucocephala foliage + 70% P. purpureum, T3: 30% E. cyclocarpum fruits + 70% P. purpureum, T4: 30% L. leucocephala foliage + 30% E. cyclocarpum fruits + 40% P. purpureum. Voluntary intake was higher in T4 (grass + leucaena + E. cyclocarpum) (P = 0.0001). Higher LW gain was observed in animals fed with T4 (P = 0.0001) and the lowest LW gains were recorded with grass (T1) and grass + leucaena (T2) (78.9 and 99.2 g/day, respectively). Similarly, the feed conversion efficiency was improved with treatment T4 (P = 0.0030). The in vitro gas production (48 h) was lower by 30 mL/0.5 g fermented DM in T4 compared with the other treatments (P = 0.0001). Apparent DM digestibility was higher in T3 and T4 (P = 0.0005). The protozoa counts were lower in T2, T3 and T4 (P = 0.0001). Higher intake, digestibility and sheep performance with diets containing grass + leucaena + E. cyclocarpum mixture arise from an improved nutritional diet as these sources have higher protein, lower cell walls and higher DM digestibility.

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The present study was conducted through two successive seasons of (2007-2009) at Fac. Agric. Exptl. Farm. Assiut Univ. to sur-vey Arthropods associated with three grapevine varieties (Mus-cat, Thompson seedless and Az-merly) and study the seasonal fluctuations of the most abundant and economically injurious pests: black vine thrips, Retithrips syri-acus Mayet and European red mite, Panoychus ulmi Koch. Data of the survey study re-vealed the presence of 20 insect species belonging to 20 genera under 14 families of 8 orders. Moreover, mite species was rep-resented by three species belong-ing to three genera under two families of two orders. Intensive and extensive observations indi-cated that the collected insect and mite species can be classified according to their economic im-portance as pests included 19 insect species and two mite spe-cies. Predators included one in-sect species and one mite species. In the first season (2007/2008) R. syriacus started with low levels in April, increased in May and the maximum number of individuals on leaves was recorded in June and July, for the three grapevine varieties. Then, the number of individuals decline rapidly during the next six months (Aug.-Jan.). In the second season (2008/2009) the population den-sity of this insect species showed low level of multiplicity on Mus-cat and Thompson seedless dur-ing April and on Azmerly during June. The population increased through July and August to ex-hibit moderate monthly averages on the three varieties. A quick augmentation respecting the in-dividuals were recorded in Sep-tember on all grapevine varieties. Through November, December and January, the monthly aver-ages gradually decreased, and the pest completely disappeared in February on all the varieties tested. On the other hand, population of P. ulmi was beginning at low level of abundance during April in the first season or March and April in the second one for the three grapevine varieties. Through May in the first season or May and June in the second one, the population density of this mite species reached its utmost levels of abundance. Then, rapid descended in the level of population density was occurred through the next months, till disappeared in February in the first season and from September in the second one on the leaves of grapevine varieties.

The present study was conducted through two successive seasons of (2007-2009) at Fac. Agric. Exptl. Farm. Assiut Univ. to sur-vey Arthropods associated with three grapevine varieties (Mus-cat, Thompson seedless and Az-merly) and study the seasonal fluctuations of the most abundant and economically injurious pests: black vine thrips, Retithrips syri-acus Mayet and European red mite, Panoychus ulmi Koch. Data of the survey study re-vealed the presence of 20 insect species belonging to 20 genera under 14 families of 8 orders. Moreover, mite species was rep-resented by three species belong-ing to three genera under two families of two orders. Intensive and extensive observations indi-cated that the collected insect and mite species can be classified according to their economic im-portance as pests included 19 insect species and two mite spe-cies. Predators included one in-sect species and one mite species. In the first season (2007/2008) R. syriacus started with low levels in April, increased in May and the maximum number of individuals on leaves was recorded in June and July, for the three grapevine varieties. Then, the number of individuals decline rapidly during the next six months (Aug.-Jan.). In the second season (2008/2009) the population den-sity of this insect species showed low level of multiplicity on Mus-cat and Thompson seedless dur-ing April and on Azmerly during June. The population increased through July and August to ex-hibit moderate monthly averages on the three varieties. A quick augmentation respecting the in-dividuals were recorded in Sep-tember on all grapevine varieties. Through November, December and January, the monthly aver-ages gradually decreased, and the pest completely disappeared in February on all the varieties tested. On the other hand, population of P. ulmi was beginning at low level of abundance during April in the first season or March and April in the second one for the three grapevine varieties. Through May in the first season or May and June in the second one, the population density of this mite species reached its utmost levels of abundance. Then, rapid descended in the level of population density was occurred through the next months, till disappeared in February in the first season and from September in the second one on the leaves of grapevine varieties.