Agriculture Reference
In-Depth Information
Faba bean
Field pea
2
Grass pea
Lentil
1.5
a)
b)
1
0.5
0
5
10
15
20
25
30
5
10
15
20
25
30
Days after infestation (DAI)
Figure 5. Mean number of pea aphids day per five plants on cool-season legumes, a)
Local varieties, b) Improved varieties.
Despite the huge difference between crop types and varieties, the pea
aphids successfully colonized and developed on all legumes and varieties
tested. Variations were observed in the growth rate of the aphids, their
colonization and preferences. All tested legume crops are recognized as hosts
of pea aphids, but there was noticeable difference in preference and
performance. Host plant varieties and growth stages of these crops were
sources of variation for the observed difference in preference and performance
of pea aphids. Aphids took long time (up to 11 days) to infest faba beans and
just 1 day to infest field peas, lentils and grass peas. The population growth
rate of pea aphids varied with the crop variety and growth stage. For each of
the crop varieties tested, the maximum growth rate of pea aphid was 153 on
local grass pea, 53 on improved grass pea, 137 on improved lentil, 112 on
local field pea, 131 on improved field pea, 400 on local faba bean and 389 on
improved faba bean.
Pea aphid preference and performance in dual- and multiple-choice
conditions varied depending on the combination of alternative choices. For
instance, lentil and field pea were found to be sensitive and died earlier under
no-choice and dual-choice conditions. However, when these varieties were
exposed to pea aphid with multiple choices, they sustained for long time but
carried less pea aphid load. The reason behind this may be that the food
availability will be higher and the pea aphid population density will be lower
per plant.
