Effect of storage time of diluted herbicides mix on their effectiveness: pre-emergency herbicides (part II)

摘要

Different types of sprayers are used in farm practice. In small farms it is getting more economical to couple spraying booms and manual spraying lances to large volume tanks. In large farms the trend is to replace the traditional system by the ready diluted mix system. In both cases a prolonged storing time of the mix in tanks or refilling vehicle, especially in rainy periods of the year is required. So, it is important to determine how long the storage time may be without causing the effectiveness of the diluted mix to decrease. That is what this paper is related to. A random block design trial was carried out during the 1991/92 crop season, at the Experimental Station of the Agronomy College of UNESP, in Jaboticabal, São Paulo, Brazil. Commercial diluted mixes of formulations of ametryne and diuron stored during 00, 05, 10, 15, 20, 25 and 30 days were field evaluated. A testimony plot was not treated. Countings of emerging weeds in a 1,2 m2 plots were perfomed at 30, 45 and 59 days after spraying. After a 95 day period a general visual control was also perfomed. Results showed that none of the storage times tested significantly influenced herbicides effectiveness, no matter what the product was. One concluded that the herbicides diluted mixes tested could be normally utilised, provided the storage time didn't exceed 30 days.