Photosynthetic inhibition in Phaseolus vulgaris II. The influence of light on herbicidal action

The influence of pre-treatment and post-treatment illumination upon the herbicidal effect produced in Phaseolus vulgaris L. cv. Berna by simeton, diuron, diquat and ioxynil was examined. The increased effect noted at lower pre-treatment and higher post-treatment levels of illumination was correlated with increased inhibition of net photosynthesis. This increased effect was ascribed to enhanced photo-oxidation.     

CONTROL OF WEEDS IN MARROWSTEM KALE BY EPTC AND SOME OTHER HERBICIDES

Summary. Two experiments on chemical weed control in marrowstem kale are reported. In the first of these three herbicides applied before sowing were compared; in the second experiment four herbicides were studied, one applied before sowing and the others applied after emergence. Of all the herbicides examined, EPTC, applied before sowing and incorporated into the seedbed, was the most satisfactory in terms of both weed control and yield of kale. Neither endothal + propham nor dinoseb + TCA proved satisfactory as pre-sowing treatments. The three herbicides applied post-emergence (all methylmercapto triazines) were ineffective for the control of Polygonum spp. and Poa annua , although fairly effective against Stellaria media and Chenopodium album . They caused considerable damage to the crop and reduced yields by at least 25%.
Le désherbage du chou moellier par l'EPTC et quelques autres herbicides     

Litterarische Berichte

Ohne Zusammenfassung     

Further Experiments on the Control of the Apple Blossom Weevil,Anthonomus Pomorum L.

The age at anthesis of tomato plants grown from weekly sowings varied throughout the year. This was related to the mean day-length from germination to anthesis, the asymptotes being an age of 40 to 50 days and a mean day-length of approximately 10 hours. Age at anthesis was also related to the total radiation received and the seasonal variation in flowering age could be explained by postulating (a) a minimal total radiation requirement for anthesis to occur and (b) a minimal age of 40 to 50 days before which anthesis could not occur. Sowings that began to flower between the autumnal and vernal equinoxes exhibited a considerable delay in attaining anthesis and the age at first flowering increased to values exceeding 110 days from sowing. The factor causing this delay was removed at approximately the vernal equinox, and a spring-like flush of flowering occurred during the month of March, with more than 20% of all the sowings beginning to flower during this one month. The data suggest that the factor responsible for this phenomenon might be light duration or it might be total radiation. It was found that the seasonal pattern of flowering exhibited a rapid increase in the weekly rate of flowering from early March to early May, followed by a progressive decline until July. From July until the following early March a low weekly rate of flowering was maintained.