. Effect of imazethapyr and imazamox soil residues on several vegetable crops grown in Ontario. Can. J. Plant Sci. 78: 647-651. Use of imidazolinone herbicides has often resulted in carryover effects on sensitive rotational crops. The effect of soil residues of imazethapyr and imazamox on several vegetable crops grown in rotation with soybean (Glycine max [L.] Merr.) was investigated over a 5-yr period in southern Ontario. Imazethapyr at 0, 100 and 200 g a.i. ha -1 was applied preemergence to soybean from 1991 to 1993. Imazethapyr at 0 and 100 g a.i. ha -1 and imazamox at 35 g a.i. ha -1 was applied postemergence to soybean in 1994 and 1995. Cabbage (Brassica oleracea L.), potato (Solanum tuberosum L.), tomato (Lycopersicon esculentum L.), sweet corn (Zea mays L.) and cucumber (Cucumis sativus L.) were planted each spring, 1 and 2 yr following preemergence imazethapyr application and 1 yr following postemergence imazethapyr and imazamox application. Potato and sweet corn showed visual injury symptoms 1 yr after preemergence imazethapyr application in 2 of 3 yr while cabbage, tomato and cucumber showed visual injury symptoms all 3 yr. Minor visual injury symptoms did not reduce yields. Cabbage was the most sensitive to imazethapyr soil residues. Cabbage yields were reduced in 2 of 3 yr, due to carryover residues from 100 and 200 g ha -1 of imazethapyr applied the previous year. Tomato and potato also showed yield reductions in 2 of 3 yr due to imazethapyr soil residues. The degree of injury and yield reduction was influenced by soil pH and soil moisture. There were no yield reductions for any crop 2 yr after imazethapyr application. Imazamox soil residues were less injurious than imazethapyr soil residues to vegetable crops grown in rotation and resulted in only minor visual injury symptoms and no yield reductions on tomato, potato or cabbage.

Sensitivity of processing sweet corn (Zea mays) cultivars to nicosulfuron/rimsulfuron. Can. J. Plant Sci. 78: 151-154. Sixteen processing sweet corn cultivars were evaluated to characterize cultivar sensitivity to nicosulfuron/rimsulfuron in field studies, conducted over a two-year period. Response to nicosulfuron/rimsulfuron varied widely, depending on cultivar and application rate. Delmonte 2038 was highly sensitive of nicosulfuron/rimsulfuron, resulting in the death of all plants. Nine cultivars showed moderate visual injury, but this did not always result in a significant yield reduction. Six cultivars were characterized as fully tolerant to field applications at rates of 25 g a.i. ha -1 . These cultivars were Reveille, CNS 710, Krispy-King, Reward, More and GH 2628.

Sixteen sweet corn cultivars, representing a range of endosperm genotypes, were evaluated to determine cultivar tolerance to nicosulfuron plus rimsulfuron in greenhouse and field studies conducted over a two-year period. Response to nicosulfuron plus rimsulfuron varied widely, depending on cultivar and application rate. In the field, four cultivars were tolerant to applications of nicosulfuron plus rimsulfuron at rates of 50 g/ha. In the greenhouse, eight cultivars were tolerant to nicosulfuron plus rimsulfuron at 25 g/ha. ‘Merit’ and ‘Silver Extra Sweet’ were most sensitive, with applications of nicosulfuron plus rimsulfuron resulting in death of all plants. ‘Miracle,’ ‘Extra Early Super Sweet,’ ‘Bunker Hill,’ and ‘Sweet Belle’ were tolerant.

17,517,5 et 2Ol10"C respectivement. Les semences imbib6es lbvent jusqu'ir 6 jours plus t6t que les semences t6moins. La concentration de la solution saline d6termine la dur6e de la p6riode de traitement. Le s6chage superficiel de la semence h temp6rature ambiante pendant I jour avant le semis n'entraine qu'une l6gdre r6duction du taux de germination et de lev6e. Le s6chage suivi d'une p6riode de conservation maximale de 21 jours ne r6duisent pas sensiblement I'effet b6n6fique de l'imbibition des semenses dans une solution saline d 1,57o, mars pour les semences imbib6es dans l'eau ou dans des solutions salines dilu6es, I'effet stimulateurb6n6fique se perd au bout de Tjours de s6chage.

The effect of soil residues of flumetsulam plus clopyralid on several vegetable crops grown in rotation with field corn was investigated over 2 yr. The effect of soil residues of flumetsulam plus clopyralid on sweet corn cultivars of varying sensitivity to acetolactate synthase (ALS)-inhibiting herbicide was also investigated. Flumetsulam plus clopyralid was applied preemergence (PRE) to field corn at 0, 50 + 135, and 100 + 270 g ai/ha, respectively, in 1993 and 1994. Cucumber, tomato, cabbage, potato, pepper, pea, and sweet corn were planted each spring, both 1 and 2 yr following the herbicide application. Cabbage was very sensitive and showed visible injury symptoms and yield reductions both years following flumetsulam plus clopyralid application. Pepper showed a yield reduction only in 1995. All other crops showed no injury or yield reductions. Flumetsulam plus clopyralid was applied PRE and postemergence (POST) to six sweet corn cultivars in 1995. These six sweet corn cultivars were replanted into the same site 1 yr later. Flumetsulam plus clopyralid severely injured three of six sweet corn cultivars in 1995, the year of application. Soil residues 1 yr later, however, did not injure or reduce yield of any sweet corn cultivars, including cultivars sensitive to ALS-inhibiting herbicides.