Chemical control of the cereal cyst nematode (Heterodera avenae) in Victoria. A comparison of systemic and contact nematicides

Abstract

The nematicides Temik (2, methyl 2 (methylthio) propionaldehyde 0-(methylcarbamoyl) oxime), Lannate (S methyl N-((methylcarbamoyl) oxy) thioacetimidate), Nemafos (0, 0-diethyl 0-2 pyrazinyl phosphorothioate), Nemacur P (ethyl 4-(methylthio)-m-tolyl isopropyl phosphoramidate), Mocap (0-ethyl S, S-dipropyl phosphorothioate), and Vydate (S-methyl l-(dimethylcarbam0~1)-N-((methylcarbamoyl) oxy) thioformidate) were tested for control of the cereal cyst nematode (Hekrodera avenae Woll.) in field experiments with wheat in the seasons 1969-70 to 1971-72 at Sea Lake, Victoria. All chemical treatments significantly reduced white cyst production and nematode carry-over in each of the three seasons. In 1969 the plots were severely damaged by field mice, and in 1970 unfavourable seasonal conditions prevented large increases in grain yield from being obtained, although significant yield increases were obtained in 1971. Temik (9 kg a.i. ha-1) and Vydate (2 kg a.i. ha-1) provided excellent nematode control and gave the best grain yield increases (880 kg ha-1). Plants from plots treated with Temik at the higher rate (9 kg a.i. ha-1) were cyst-free in each experiment, and hlocap used at the same rate was severely phytotoxic. In a resowing experiment, all 1969 chemical treatments significantly reduced white cyst production and lowered nematode carry-over in 1971, although only four of the treatments provided significant increases in grain yield viz (Temik 9 at 2 kg a.i. ha-1 with added sulphate of ammonia, and Nemafos and Mocap both at 9 kg a i ha-1). Grain from plots treated with Temik and Lannate at the higher rate (9 kg a.i. ha-1) was analysed for the presence of chemical residues. No Lannate residues were detected, and Temik residues were less than 0.1 p.p.m