| dc.description.abstract | Control of barley fly Dolia fla7ibasis Stein (Diptera:
Anthomyiidae) with resistant varieties and insecticides.
Field experiment awere carried out to determine the
effects of infestation of D. flavibasis on growth and yield of
barley. The effects of the attack on the malting quality and
commercial value of harvested barley crop was also assessed.
Attacked plans suffered a check in their growth and were
observed to compensate by recovery growth. The slow rate of
development and compensatory growth delayed ripening. In
attacked barley, the shoots developed unevenly and the ears
did not ripen evenly. D. flavibasis infestation caused high
yield losses. Highest yield losses occurred in varieties
Proctor, Tumaini, K. Research and MP'IT 169 - 2Y. The lowest
yield loss occurred in Can B35/2. However, E. flavibasis
attack did not affect the grain quality, hence no effect on
the malting quality of barley. The pest incidence did not
reduce the commercial value of the harvested barley crop.
Five barley varieties viz Procter, K. Research, Tumaini,
MP"J.'"T 169 - 2Y and Can B35/2 were tested in the field to
compare their resistance to D.flavibasis. Despite variation
in results, Can B35/2 be identified as moderately resistant
variety useful for reference in further work. The barley
varieties were observed to recover their growth after the infestation.
Although it was difficult to identify the mechanism of
resistance, visual growth recover scores in the field experiments
suggested some form of tolerance. However, observed grain
yield differences between varieties indicated resistance could
be due to many unknown factors such as environmental or varietal
yield potential.
The response of barley varieties to attack by flavibasis
was studied in the greenhouse. The effects of infestation were
quantified. 'Barley plants infested with D. flavibasis larvae
at 11 - 12 growth stages were virtually killed, while plants
infested at 13th growth stage survived. Infested plants suffered.
a check in their growth and development but were later observed to
recover their growth. Also in response to attack proportionately
more tillers were produced by infested plants. This suggested
tolerance as the mechanism of resistance.
Field experiments carried out on the chemical control of
barley fly Q. flavibasis showed carbofuran 5c granules as an
outstanding preventive seed-dress treatment, with 4Kg a.i/Ha
giving lCC%control to D. flavibasis larvae. Aldrin 4CDk wettable
powder was the second effective seed-dress treatment. Phosphamidon
5 S.C.w. and trichlorphon 95 S .P. were the most promising
foliar sn.ray insecticides evaluated for control of D. flavibasis
larvae on barley. Applications of seed-dressings of both
carbofuran granules and aldrin 40J.t wettable powder for control
of D. flavibasis larvae significantly improved grain yield. | en |
