Effects of insecticides and cultivars on panicle-feeding insect pest infestations and grain yield of sorghum (Sorghum bicolor (L.) Moench) in northern Ghana

Background Panicle-feeding insects are a challenge in sorghum (Sorghum bicolor (L.) Moench) cultivation but most farmers do not protect the crop. Here, the effects of pest management in different sorghum cultivars on grain yields and the financial returns after protecting the crop from panicle-feeding insects was studied. Results There were significant insecticide treatments × cultivars/genotypes interaction effects for Stenodiplosis sorghicola, Clavigralla tomentosicollis, Nezara viridula, Dysdercus fasciantus and Riptortus dentipes. Generally, pest infestations were higher in the untreated control compared to K-Optimal- or NSO-treated sorghum. Infestations were also higher in compact-headed cultivars (Dorado and Kapaala) compared to those with open heads (CSSOR 08-V01 and CSSOR 10-V07). Damage was approximately 1.7-fold higher in the untreated controls than in NSO or K-Optimal. Grain yields were about 14% higher in NSO or K-Optimal treated sorghum than in controls. Gross margins were between 16- and 35-fold higher in protected sorghum compared to the untreated ones. Conclusion These findings suggest that an effective integrated pest management strategy for sorghum farmers must comprise cultivars that do not have compact heads, and the use of about two sprays of NSO or a synthetic pyrethroid when high numbers of panicle-feeding insects are observed during the growing season. Judicious use of insecticides and the “right” cultivar will improve the profitability of sorghum farmers with gross marginal returns that are at least 15-fold higher than that obtained by farmers who adopt only good agronomic practices without insecticide sprays.

First record of Stenodiplosis sorghicola on sorghum in Greece

In October 2007, the sorghum midge Stenodiplosis sorghicola (Coquillett) (Diptera: Cecidomyiidae) was recorded for the first time in Greece. Its occurrence was noticed in an experimental sorghum cultivar at Aliartos, near Athens, in Viotia region. Information on its morphology, biology and distribution is given.

Host-plant resistance and biopesticides: ingredients for successful integrated pest management (IPM) in Australian sorghum production

There are two major pests of sorghum in Australia, the sorghum midge, Stenodiplosis sorghicola (Coquillett), and the corn earworm, Helicoverpa armigera (Hübner). During the past 10 years the management of these pests has undergone a revolution, due principally to the development of sorghum hybrids with resistance to sorghum midge. Also contributing has been the adoption of a nucleopolyhedrovirus for the management of corn earworm. The practical application of these developments has led to a massive reduction in the use of synthetic insecticides for the management of major pests of sorghum in Australia. These changes have produced immediate economic, environmental and social benefits. Other flow-on benefits include providing flexibility in planting times, the maintenance of beneficial arthropods and utilisation of sorghum as a beneficial arthropod nursery, a reduction in midge populations and a reduction in insecticide resistance development in corn earworm. Future developments in sorghum pest management are discussed.

Ocorrência da mosca-do-sorgo Stenodiplosis sorghicola (Coquillett) (Diptera: Cecidomyiidae) em genótipos de sorgo em Rio Branco, AC, Brasil

Este trabalho relata a primeira ocorrência de Stenodiplosis sorghicola (Coquillett) no Estado do Acre, Brasil, e a incidência dessa praga em diferentes genótipos de sorgo. Panículas foram coletadas dez dias após o início do florescimento e colocadas em caixas de emergência. S. sorghicola ocorreu em sorgo forrageiro e granífero, sendo a incidência maior no primeiro, no qual o genótipo 698005 foi o mais atacado. A presença de S. sorghicola, em plantios experimentais de sorgo no Acre, revela que tal inseto ocorre na região, sobrevivendo, provavelmente, em outras espécies do gênero Sorghum.