The analysis of the effect of different herbicides on Johnson-grass in maize

The Johnson-grass (Sorghum halepense /L./Pers) is a perennial monocotyledon, its gen centre is in the Near East. Botanically this weed belongs to the monocotyledone class, Poaceae (Gromineae) family and within this, together with the maize to the Andropogonoideaei subfamily. At the time of the First National Weed Survey (1947-1953) it has not been found in Hungary. In the periods of the 2nd (1969-1971), 3rd (1987-1988) and 4th Survey it occupied the 94th, 18th and 10th place of importance, respectively. Because of its rapid multiplication and spreading after the second weed survey (1969-1971) and because of its very complicated and difficult control, the Plant Protection Division of our Ministry of Agriculture ranged it in 1974 into the category of "Dangerous weed". Johnson grass is the 6th most important weed in the world. A small plot field trial was carried out in Szabadszentkirtly (12th May 2006) in maize. The effect of pre- and post emergent herbicides was investigated against Johnson grass germinating from seed and sprouting from rhizome. The treatments were done in 4 repeats with Stomp 330 EC, Dual Gold 960 EC, Merlin WG, Wing EC, Guardian Max and Monsoon herbicides. The number of weeds germinating after spraying and the number of damaged weeds were counted and compared to the control plots 10 days after the treatments and then weekly. Parallel to the field trial, a "soil culture in pots" trial in glasshouse was also carried out in which the effect of the above mentioned herbicides was investigated against Johnson grass germinating from seed. During on experiments all the herbicides showed an excellent herbicide activity until the 2nd week of treatment, although the precipitation of the second week was only 8.4 mm. Under the given experimental conditions the best herbicide effect until the 4th week, in both experimental phases were given by Merlin WG.