Agriculture Reference
In-Depth Information
density the lower the rate of reproduction and the longevity of aphids.
Aphid population dynamics studies also showed that aphids prefer cool
and dry climate, nevertheless warm episodes are necessary for
reproduction. Lower altitudes are therefore found good hot-spots for the
aphids. Our research station (Adet Research Center, Amhara, Ethiopia) is
located at 2240 m a.s.l. where the aphids are less important while 45 km
north the altitude descends 400 m lower than our station, gets warmer and
grass pea production has almost stopped there because of these aphids.
Aphid numbers steadily increased from seedling stage to pod setting, and
then drastically fell at maturity. Lentils and grass peas were more suitable
hosts than faba bean and field pea. In Ethiopia, pea aphids were first
reported in cool and dry regions of the extreme north, which later
extended their range to even lower altitudes and warmer areas.
Management studies carried out include botanicals, detergents, kerosene
and some of the more conventional and aphid-specific pesticides.
Promising botanicals included spray of capsicum juice, kerosene (despite
its phytotoxicity) and detergents. Parasitism of aphids by
Aphidius
species and predation by coccinellid larvae and adults was high but they
came late long after damage was inflicted to the crop. The series of
studies carried out over the years helped to determine the status of the
pest in the area and point out some of the environmentally safe
management options. Planting susceptible legumes may have to be
limited to places where the aphid is not endemic or better use aphid-
specific pesticides (such as pirimicarb). Spraying alternate hosts during
the off-season to break the cycle of infestation, determining the rate and
frequency of botanicals such as capsicum, and ensuring the survival of
coccinellids and aphid parasitoids during the offseason can be the next
research agenda.
1.
I
NTRODUCTION
The cool-season food legumes are important grain products in Ethiopia.
Field pea (
Pisum sativum
L.), faba bean (
Vicia faba
L.), lentil (
Lens culinaris
Medik.) and grass pea (
Lathyrussativus
L.) are the most important ones. The
Ethiopian highland plateau is suitable for these cool season legumes because it
mimics the more temperate climate of the Mediterranean region where most of
these legumes are believed to have originated. Ethiopia is believed to be the
second largest faba bean producer in the world only after China (Abebe et al.,
2014). Because most people in Ethiopia cannot afford animal protein, legumes
have long constituted their protein diets for millennia.
