Biology, host preference, host suitability, and plant resistance studies of the barley stem gall midge and Hessian fly (Diptera:
General Material Designation
[Thesis]
First Statement of Responsibility
S. Lhaloui
Title Proper by Another Author
Cecidomyiidae) in Morocco
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
Kansas State University
Date of Publication, Distribution, etc.
1995
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
184
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
Kansas State University
Text preceding or following the note
1995
SUMMARY OR ABSTRACT
Text of Note
The barley stem gall midge, Mayetiola hordei Keiffer, and the Hessian fly, M. destructor (Say), are the most serious pests of barley and wheat in Morocco. The biology, host preference, host suitability, and plant resistance for both species were studied. Results showed that the biology and life cycle of barley stem gall midge are similar to those of Hessian fly. The barley stem gall midge breeds by unisexual progenies and has two feeding instars and a nonfeeding third instar. All instars of the barley stem gall midge required longer developmental time than Hessian fly. Ovipositional preference tests showed that Hessian fly females consistently preferred wheat over barley, while barley stem gall midge females strongly preferred barley over wheat. Hessian fly larvae were able to survive and develop on barley, but barley stem gall midge larvae were not able to develop normally on wheat. This indicated that Hessian fly can reproduce successfully on barley, while barley stem gall midge can rarely reproduce on wheat. Many wild grasses were suitable ovipositional and larval hosts of Hessian fly. Cultivated wheat was, however, significantly more preferred than wild species. The most preferred species for oviposition were also the most suitable larval hosts, and had significantly larger stem-leaf angles, wider leaves, and lower leaf pubescence than other species. Many wild Hordeum species were also suitable ovipositional and larval hosts for the barley stem gall midge. However, resistance (antibiosis and antixenosis) to both species was identified in these wild grasses. Screenings of the barley germplasm for resistance to barley stem gall midge revealed that most Moroccan germplasm was susceptible. However, various levels of tolerance were expressed in this germplasm. Screenings of the wild barley species showed that many accessions were heterogeneous; some were selected as having adequate levels of resistance. Three New Zealand barley cultivars were resistant to biotype L Hessian fly in the United States and to Moroccan Hessian fly, but were susceptible to barley stem gall midge. Resistance was expressed mainly as antibiosis and was not affected by increasing temperature up to 30C.