Effect of different silica sources on cotton leaf worm population in sugar beet plants, and their influence on sugar beet yield

Abstract

Field and laboratory experiments were conducted at Taifaa region and Agricultural research station, Kafr El-Sheikh Governorate, during two successive seasons 2019/2020 and 2020/2021. To estimate the efficiency of alternative materials for controlling Spodoptera littoralis, some silica sources were incorporated to the soil such as (straw and husk) and sprayed on the plants, spray such as potassium, magnesium, sodium silicate and Si NPs. Burnt husk added to the soil at the rate of 200 g/m2 gave the highest reduction 50.48, 48.72%, highest root yield 25.16, 24.60 ton/fed, foliage yield 8.99, 8.60 ton/fed, sucrose percentage 16.71, 17.43%, T.S.S%20.40, 20.60%, purity 81.91, 84.61% and white sugar 4.20, 4.29 ton/fed in the two seasons, respectively. Spray of silica NPs at the rate of 4g/L gave the highest reduction 68.46, 77.81%, root yield 26.03, 26.01 ton /fed, foliage yield 8.60, 8.36 ton/fed, sucrose percentage 18.80, 19.00%, TSS% 22.90, 22.60%, Purity 86.46, 84.07% and white sugar 4.89, 4.94 ton/fed in the two seasons, respectively. In the laboratory, the toxic effect of each of silica NPs, potassium silicate, magnesium silicate and sodium silicate for 2nd larvae instar after 96 hr., was and found that Lc50values were 0.079, 0.212,0.239 and 0.261 g/L. While the corresponding values for 4th after 96 hr., were 0.120, 0.218, 0.261 and 0.594 g/L, respectively.