Utilisation of Wild Gramineous Plants for Management of Cereal Stemborers in Africa

Abstract

Field trials in Kenya demonstrated that the forage grass, Sorghum vulgare sudanense (Sudan grass) attracted greater oviposition by stemborers than cultivated maize, resulting in significant increase in maize yield. On the other hand, the non-host forage plant, Melinis minutiflora (molasses grass), when inter-cropped with maize, repelled gravid stemborer females from ovipositing on maize, resulting in significant reduction in stemborer infestation. Using these trap-and repellent gramineous plants, a novel pest management approach based on a 'push-pull' or stimulo-deterrent diversionary strategy is being developed where stemborers are repelled from the food crop and are simultaneously attracted to a discard or trap crop. The plant composition and permanence of habitat surrounding maize fields also influence the abundance of natural enemies that invade agroecosy stems once a pest population is present. It may be advantageous to promote the growth of native Gramineae and other wild plants which minimise, or even suppress, population growth of pests during noncropping seasons, but still provide a suitable habitat for natural enemies.Resume-Des essais de terrain au Kenya ont prouve que l'herbe fourragere, Sorghum vulgare sudanense (herbe du Soudan) attirait plus de foreurs de tiges pour la ponte que le mai's cultive, entrainant une augmentation significative de la recolte de mai's. D'autre part, la plante fourragere non-hote, Melinis minutiflora (herbe melasse), une fois en culture mixte avec le mai's, empechait des foreurs de tiges femelles gravides de pondre sur le mai's, ce qui reduisait significativement l'infestation du mai's par les foreurs de tiges. I/utilisation de ces plantes graminees pieges et repulsives, une approche nouvelle du controle des ravageurs basee sur une strategie diversionniste de 'pousse-tire' ou de 'stimulation-deterrence' est en train d'etre developee la ou les foreurs de tiges sont repousses loin des cultures de consommation et sont simultanement attires vers une plante rebut ou piege. La composition botanique et la permanence de l'habitat entourant les champs de mai's influencent aussi 1'abondance des ennemis naturels qui envahissent des agroecosystemes des qu'une population de ravageurs est presente. II serait avantageux de promouvoir la croissance des graminees indigenes et d'autres plantes sauvages qui minimisent ou meme inhibent la croissance des populations des ravageurs durant les saisons de jachere, tout en assurant un habitat favorable pour les ennemis naturels.

Opportunities for Napier Grass (Pennisetum purpureum) Improvement Using Molecular Genetics

“…In crop land management systems, it is used as a mulch to control weed infestation and soil erosion [2] and as a trap plant in the push-pull strategy, a pest management practice which uses repellent intercrop 'push' plants and attractant trap 'pull' plants [23] for insect pest control in Africa, particularly for the maize stem borer [24,25]. Plants are also used to scavenge pollutants, such as heavy metals, and Napier grass has been used in phytoremediation strategies, for example for the cleanup of cadmium-affected soil, reducing the concentration of cadmium to a depth of 15 cm in soil [17].…”

First record of the egg parasitoids of Chilo partellus (Swinhoe, 1885) (Lepidoptera: Crambidae) in Turkey unveiled by DNA Barcoding

“…The invasive pest, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), commonly known as spotted stem borer, is one of the most serious pests of cereal crops, especially maize and sorghum in Asia and South Africa. Chilo partellus has a broad host range, including both wild and cultivated plants (Khan et al, 1997;Rebe et al, 2004), but is of most concern as a pest of maize. Chilo partellus has been reported to cause severe yield losses in maize throughout its geographical distribution.…”

Intercropping Empower Reduces Insect Pests and Increases Biodiversity in Agro-Ecosystem

“…Non-host crops that are grown in intercropping system also can emit organic chemicals which adversely affect the pest insects [27]. Other explanation can be applicable that reduction of pest population can be done due to attraction of biocontrol agents (natural enemies) of insect pests by the emission of volatile organic compound or acts repelling the insect pest [33] [34] [35] [36] [37]. In our study, data of natural enemies were not collected, however we can hypothesize that intercropping system enhanced biocontrol agents that reduced pest population in mustard crop.…”