Effect of Sources and Concentrations of Potassium Foliar Application on Yield, Quality and Leafminer Infestation (Liriomyza trifolii) in Gerbera (Gerbera jamesonii 'stanza')

In this research the foliar application efficiency of potassium salts in different concentration was investigated on yield, quality and leaf miner (Liriomyza trifolii) control of hydroponically - grown cut flower Gerbera jamesonii 'stanza', in one year experiment, in 2008. Young plantlets were either sprayed with three different potassium salts including; KNO3, K2SiO3 and K2SO4 and 3 levels of K: (0, 1.5 and 3 g L-1) was sprayed 2 times a week during the trial. The treatments were laid out in a complete randomized design with 5 replicates per treatment (each replication was included four pots). The results indicated that all K treatments increased potassium leaf content and the yield significantly at 1% level and among the all, KNO3 had the highest yields. In KNO3 and K2SiO3 treatment at (3 g L-1) and K2SO4 at (1.5 g L-1), the quality components of the products were significantly improved compared to control. Percentage of leaf miner infestation was reduced at (3 and 1.5 g L-1), for 12.5% and 7.8% respectively, in potassium silicate treatment. The data showed that there was a negative significant correlation coefficient between potassium foliage and leaf miner damage in potassium silicate source. In contrary, no control effect consider in other potassium sources. This result showed the differences among the potassium sources in gerbera.