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Role of herbicide (metalachlor)
and fertilizer application in integrated management of
Striga asiatica in maize in Malawi
V.H. Kabambe1,2, A.E. Kauwa1 and
S.C. Nambuzi1
1Chitedze
Research Station, P.O. Box 158, Lilongwe, Malawi.
2Bunda College of
Agriculture, P.O. Box 219, Lilongwe, Malawi.
Accepted 10 January, 2008
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The
parasitic weed species Striga asiatica (L.) Kuntze is
one of the major constraints in maize production in Malawi.
The effects of metalachlor (as DualTM Magnum 960
EC), a pre-emergence herbicide, with 69N:21:P2O5:4S
kg ha-1 and without fertilizer application, on
maize growth and Striga suppression, were
investigated at 5 sites in 2000/’01 season and 6 sites in
2001/’02. The use of metalachlor at 2.2 kg ha-1
gave no considerable phytotoxic effects on maize plants.
Application of metalachlor significantly suppressed
Striga emergence across all sites in 200/’01 and not in
2001/’02. Metalachlor application increased yields from 1448
to 1793 kg ha-1 in 2000/’01, and from 1677 to
2077 kg ha-1 in 2001/’02. On the overall, the use
of fertilizer was superior to herbicide use in increasing
maize yields. Yields were generally low as, in most cases,
sites with Striga are low in productivity. Due to
this association between poor site productivity and
Striga, an integrated approach which tackles both
problems is suggested. For example, rotation with legumes is
strongly recommended not only to reduce Striga seeds
in the soil, but to improve fertility. The increased
productivity in subsequent years would then allow sufficient
yields to cover other inputs such as herbicides, fertilizer
and improved seed.
Key
words: Witchweed, Zea mays L., metalachlor,
on-farm fertilizer responses. |
