RA 00110.pdf - OAR@ICRISAT

eflexa, and other scarab beetle species have sometimes
been observed on developing grain.
Bugs damage grain at the milk stage. The symptoms
are chalky black spots on the grain or atrophied
grain. Agonoscelis versicolor, A. pubenscens,
Diploxys spp., and Spilostethus spp. are the most
frequent species.
Forficula senegalensis is found in the panicle
sheath, and produces reddish-brown streaks on the
leaves which subsequently turn yellow. They also
devour the florets and milk-stage grain.
Melyris abdominalis (Coleoptera: Melyridae) is a
pest of late millets in southern Senegal, causing variable
damage.
Economic Importance of Pearl Millet
Pests
Figure 3. Raghuva albipunctella damage on millet
heads.
of minor importance at present. But incidence
increases in varieties with compact heads that support
these insects and protect them from parasites.
Several species of blister beetles known to be
millet pests are found in the Sahel. Significant field
infestation of Psalydolytta fusca, P. vestita P. flavicornis,
Cyaneolytta spp., Mylabris holosericea, and
M. palhpes has been reported in Gambia, Mauritania,
and Mali (Magema 1984, Doumbia et al. 1984,
Zethner and Oliver 1984). The distribution and relative
importance of these insects is not yet well
known. Heavy infestation at flowering on local cultivars
can cause considerable damage. Adults devour
the pollen and female flowers and are responsible for
grain abortion and head sterility. Time of population
build up varies for each location and year, but
occurs most frequently in September (Doumbia et
al. 1984).
Pachnoda spp., Anomala senegalensis, Rhinyptia
There is consensus that insect pests on the whole are
injurious to pearl millet; however, specific studies
have rarely been conducted on the relative economic
importance of the different species or complexes.
Studies in Nigeria and Senegal confirm the importance
of stem borers (Harris 1962, Bonzi 1977,
NDoye 1977), millet midge (Coutin and Harris
1968), and spike worms (Bos 1983), as evidenced by
frequent losses recorded in these countries. Recently,
blister beetle damage has been observed in Gambia,
Mali, and Mauritania, but no accurate evaluation
has been made of the situation. Spike worms have
assumed major pest status since the recent drought,
and are a serious problem of pearl millet crops.
Control Methods
Cultural Techniques
Fire
It is a common practice in the rural Sahel to light
fires around millet fields at night. This has been
known to reduce blister beetle populations on the
heads (Magema 1984).
Tillage
Deep plowing either at the end of the rainy season or
before planting the next crop can reduce large populations
of diapausing Raghuva pupae in the soil.
They are exposed to predators, mainly birds, or are
dessicated (Vercambre 1978).
198