Maize is the third main cereal crop after wheat and rice in Pakistan,
and second after wheat in Khyber Pukhtunkhwa. Horse purslane (Trianthema
portulacastrum L) a member of family Aizoaceae, is a common weed of
maize, cotton and vegetables all over Pakistan (Hashim and Marwat,
2002). Due to indeterminate habit, vegetative and reproductive growth
continues for the entire life span (Nayyar et al., 2001). Out of 69 weed
species T. portulacastrum was realized as the most aggressive weed of
maize crop (Kumar and Singh, 1983). At a density of 12 plants m-2 of T.
portulacastrum gave lower maize yield of 3.54 t ha-1 than weed-free
plots 3.89 t ha-1 (Ansar et al., 1996), and infestation can lead to
32.3% losses in maize crop (Balyan and Bhan, 1989). Horse purlane caused
25 million dollars loss to maize production each year in Pakistan (PhD
Thesis of Muhammad Saeed).