Insect resistant sorghums in pest management

Abstract

The agroecosystem is the basic unit of consideration in the integrated pest management approach. The target crop within this ecological system and its level of susceptibility to insect pest species is of fundamental importance, and can be altered genetically through breeding for pest resistance. The relative level of pest resistance as influenced by pest density, demands a knowledge of pest density and plant damage (yield) relationships. An understanding of these relationships leads to the determination of economic injury levels and subsequently to the establishment of dynamic economic threshold levels.Comparing the economic injury level of insect resistant cultivars to that of susceptible cultivars defines the resistance level and provides the base-line data on which to quantify the effects of other direct control tactics and natural pest density suppressing agents.Insect resistant sorghums are used as a model to examine the unique values of this tactic as a component in an integrated pest management strategy; the role they play, and how they influence other direct control and support tactics.Resume-L'agroecosysteme est Punite de base pour une approche de lutte integree. Dans cet ecosysteme, la culture-cle et son niveau de susceptibilite aux especes d'insectes ravageurs sont fondamentals et peuvent etre modifies par l'amelioration genetique de la resistance aux especes nuisibles. Une connaissance des relations densite d'insectes et perte de rendement est necessaire car le niveau de resistance depend de la densite des insectes presents, la comprehension de ces relations permet de determiner les seuils de pertes economiques et done d'etablir une echelle dynamique des seuils d'action. La comparaison des seuils de pertes economiques des varietes resistantes et des varietes susceptibles definit le niveau de resistance et fournit des donnees de base qui permettent de quantifier les effets de tactiques de controle direct ou d'agents naturels suppresseurs d'insectes.Les sorghos resistant aux insectes sont utilises comme modele pour etudier les caracteristiques uniques de cette tactique en tant que composante d'une strategie de lutte integree. Le role de ces sorghos et la maniere dont ils influencent les methodes de controle direct et indirect sont egalement etudiees.

Oviposition Preference and Offspring Performance of a Wheat MidgeSitodiplosis mosellana(Géhin) (Diptera: Cecidomyiidae) on Defended and Less Defended Wheat Plants

“…Preferences for a narrow range of host stages are characteristic of gall midges such as Contarinia sorghicola Coquillet and Contarinia tritici (Kirby) that also oviposit on cereal inßorescences. These midges prefer even narrower ranges than S. mosellana, at ßowering for the former and at spike emergence for the latter, although no association between oviposition preference and subsequent offspring performance has been reported previously (Barnes 1956, Houpert 1972, Teetes 1985.…”

Rice Pest Management and Biological Control

“…According to Teetes ( 1985 ) the reasons attributed are failure of entomologists and plant breeders to complete their assignment after recognizing the insect resistant germplasm, lack of farmers interest to accept and use resistant cultivars to insect; tendency to separate crop production and crop protection, and failure to generate adequate information about the pests and resistant cultivars. Besides from resistance cultivar, for all types of pests, especially weeds and fungal pathogens, environmentally friendly methods of control are essential to lessen their ever-increasing environmental impact as intensifi cation of production continues.…”

A Population Level Temperature-Dependent Model of Seedling Johnsongrass (Sorghum halepense) Flowering

“…It is also an alternative ovipositional site for sorghum midge (Contarinia sorghicola Coquillett) that can later disperse to nearby grain sorghum (Sorghum bicolor (L.) Moench.) (28). Therefore, sorghum midge management systems are highly dependent upon effective johnsongrass management.…”