Effect of pre-emergence herbicides on growth parameters of green pea.

Green pea (Pisum sativum L.), is one of the important vegetable crop in Hungary. Chemical weed control has an important role in pea growing. Pre-emergence herbicides are used most frequently in a green pea culture because they eliminate competition between crop plant and weeds even at the critical early growth stage. Preemergence treatment combined with mechanical methods makes unnecessary the post-emergence protection. Herbicides with different mode of action can influence the growth of pea and cause phytotoxic symptoms. Sensitivity of plant varieties against herbicides is different in the first place due to the thickness ofleave's wax layer. The aim of our experience was to study the effect of five pre-emergence herbicides with different mode of action on the fresh and dry matter production and growing of a green pea variety (Pisum sativum cv. Petit Provencal). The examined herbicides were Pivot (imazethapyr), Proponit 840 EC (propisochlor), Sencor 70 WG (metribuzin), Stomp 330 (pendimethalin), and Afalon Dispersion (linuron). Pot experiments were carried out under greenhouse conditions in four replications. Herbicides were applied in the suggested and double doses. Four weeks after sowing the length, fresh- and dry weight of the shoots and the roots of pea were determined. It was an interesting observation that Pivot raised fresh weight significantly. Sencor 70 WG caused the most dramatic fresh mass reduction. We have got similar tendencies in dry matter production of green pea samples. Double rate of Stomp 330 and Sencor 70 WG decreased length of shoots and roots significantly. We established that examined pre-emergence herbicides could influence growth parameters to a different extent. Sencor 70 WG strongly inhibited growth of pea and caused severe phytotoxic symptoms. Double dose of Proponit 840 EC and Stomp 330 also damaged the pea but to a lesser extent. Afalon Dispersion and Pivot proved to be the most suitable herbicides; pea wasn't sensitive to these chemicals. Due to joining to EU permission of Pivot was cancelled in Hungary.