Print version ISSN 0100-8358
VICTORIA FILHO, Ricardo; MOREIRA, Célio S.; SHIMOAMA, Natalino Y. and SHINOHAR, Rosa K.. Continuos use of herbicides in citros (Citrus sinensis (L.) osbeck: II - ffects ondevelopment, yield and fruit quality. Planta daninha [online]. 1991, vol.9, n.1-2, pp.102-113. ISSN 0100-8358. http://dx.doi.org/10.1590/S0100-83581991000100011.
The research reported in this paper was conducted at the Conchal county in Sao Paulo State, Brazil, in a Red Yellow Latosol with 1,75% of organic matter, with the objective of studyng the effect of continuous use of selected herbicides on the development, yield and fruit quality, of a 'Pera' citrus orchard, grafted on 'Limão - Cravo (Citrus Limonia) . Random blocks experimental de sign with 12 treatments and 4 replicates was used. The treatments and herbicide application rates(kg /ha) were: terbacil at 3.2; simazi ne at 4.0; ametryne + secbumetone at 4.5; dichlobenil at 5.0; diuron at 3.2; bromacil at 3.2; bromacil + diuron at 3.2; paraquat at 0.6; glyphosate at 1.61 and MSMA at 1.37 and two contro1 plots manually tilled, one yearly and other whenever weeds covered 25% of the plot. The orchard was planted in may 1975, and the first herbicide application was done in october 1977. The area of each plot was 54 m2 (3,0 x 18,0 m) with 4 plants per plot The last herbicide application was done in 1982. The effect on plant development was measured through the stem diameter at 10 cm above the bud union, canopy diameter and height two times per year. Yield was mea measured harvesting the fruit s of 4 plant s per plot. The fruit quali ty was evalu ated by measuring the longitud inal and transvers al diameter, albedo, weight and number of seeds, average fruit weight, jui ce %, soluble solids %, acidi ty and production in kg per tree . The results showed no effec t the herbicides on both development and yield of the plant s. The effe ct on fruit quality was minimal.