Abstract:
Coffee yields are primarily insects-limited. This study was conducted to determine the
susceptibility of four common varieties which are under expansion in Rwanda. The influence of
four coffee varieties BM71, BM139, Jacksson2/1257 and Pop3303/21 on life history parameters
of Toxoptera aurantii was studied in a controlled environment. The colony of T. aurantii was
reared on varieties of coffee in the laboratory at 22 ± 1°C and photoperiod16-8h (L:D). The
survivorship, the number of offspring in the F1 generation (?lxmx), the intrinsic rate of natural
increase (rm), the finite rate of increase (?) and the mean generation time (T) on each coffee
variety were compared with host plant susceptibility. Results showed that there was a significant
difference among coffee varieties for F1 generation (?lxmx). The population reared on BM139
had the highest intrinsic rate of natural increase (rm = 0.354 individuals per day) and population
doubling time (t2) was 2.00 days while the population reared on BM71 had intrinsic rate of
natural increase (rm) was 0.237 and predicted time to double the population (t2) was 2.92 days.
Variety BM71 was less susceptible to T. aurantii while Jackson2/1257 was the most susceptible
variety. Other varieties were moderately susceptible. Variety BM71 could prove useful in the
development of an integrated pest management program for T. aurantii. |
