Plant Silicon Amendment Does Not Reduce Population Growth of Schizaphis graminum or Host Quality for the Parasitoid Lysiphlebus testaceipes.

Interactions between different pest control methods can affect Integrated Pest Management efficiency. This study sought to evaluate (1) if Si accumulation is related to the level of constitutive resistance in sorghum genotypes, (2) the level of Si induces resistance by antibiosis in sorghum genotypes with different levels of constitutive resistance to Schizaphis graminum (Rondani) (reared individualized or in colonies), and (3) the fitness of Lysiphlebus testaceipes (Cresson) in aphids reared on Si-treated and untreated plants. Several experiments were conducted under greenhouse conditions, using sorghum genotypes with different levels of resistance grown in pots with or without the addition of Si to the soil. The susceptible (BR007B), moderately resistant (GB3B), and highly resistant (TX430XGR111) genotypes all absorbed more Si when it was added to the soil compared with when it was not amended. However, the final Si content of treated plants was not related to the level of constitutive resistance among treated genotypes. While Si soil application did reduce the fecundity of individualized aphids reared on the susceptible and moderately resistant sorghum plants, it did not reduce populational growth of aphid colonies, independent of the level of plant's constitutive resistance. Parasitoid (L. testaceipes) had higher weight when reared from aphids fed on plants with added Si. Sorghum × constitutive resistance × S. graminum interactions were affected by plant Si content only for individualized aphids but not for aphid colonies. Sorghum × S. graminum × L. testaceipes interactions suggest that Si can have, overall, a positive effect on the biological control of S. graminum.

Parâmetros zootécnicos e desenvolvimento da moela de frangos de corte em dietas de sorgo grão e a inclusão de carotenoides / Zootechnical parameters and gizzard development of broilers fed with sorghum grain and carotenoid supplementation

Objetivou-se avaliar a substituição do milho pelo sorgo grão, moído ou inteiro, e a inclusão de carotenoides sintéticos em rações de frangos de corte, sobre parâmetros zootécnicos e desenvolvimento da moela. Utilizaram-se 960 frangos, machos e fêmeas, da linhagem Cobb 500, que foram submetidos a quatro dietas: à base de milho (M), à base de sorgo moído (SM) ou ainda acrescido de carotenoides sintéticos (SMC) e à base de sorgo inteiro (SI). Foram avaliados peso vivo, consumo de ração, conversão alimentar, rendimento de carcaça e cortes, peso de moela. A ração de SI proporcionou maior desenvolvimento de moela, embora, aos sete dias, não tenha havido diferenças no peso vivo e na conversão alimentar entre as dietas. SM e SMC proporcionaram maiores valores de peso vivo aos 28 dias do que SI. As conversões alimentares real e tradicional aos 40 dias foram semelhantes para as rações de sorgo, com um melhor rendimento de carcaça em SM e SMC. O sorgo moído pode substituir integralmente o milho nas rações para frangos de corte, sem comprometimento de desempenho e rendimento de carcaça, e, na forma grão inteiro, é zootecnicamente viável.(AU)

This study aimed to evaluate the replacement of corn with ground or whole grain sorghum and the inclusion of carotenoids in broiler feed on zootechnical parameters and gizzard development. A total of 960 Cobb 500 broilers, half of each sex, were submitted to four feeds: ground corn (M), ground sorghum (SM) ground sorghum with carotenoid supplementation (SMC) and whole grain sorghum (SI). Body weight, feed intake and feed conversion, carcass and cuts yield, gizzard weight were evaluated. SI feed provided a greater development of gizzard, however at 7 days there were no differences in body weight and feed conversions between diets. SM and SMC provided higher values of body weight at 28 days than SI feed. Feed conversion at 40 days were the same for the sorghum feeds with a better carcass yield in SM and SMC. Ground sorghum can completely replace corn in broiler diets without compromising performance and carcass yield, and whole grain sorghum is zootecnaly viable.(AU)