SUSCEPTIBILITY OF SOME MANGO VARIETIES TO THE BUD MITE ERIOPHYES MANGIFERAE (SAYED) AND MAL-FORMATION DISEASE AND THE RELATION OF MITE INFESTATION TO MALFORMATION DISEASE

In field study, Eleven mango varieties, (Mangiferae indica L.) at Sharkia, Ismailia, and Fayoum Governorates, were examined to estimate the population fluctuation of the bud mite Eriophyes mangiferae Sayed, their susceptibility to mite infestation, the relation between the mite infestation and chemical contents of mango buds and the correlation between the bud mite and malformation disease. The highest population occurred during Sept. to Jan. or Feb. and the lowest population was existed during Mar. to Jun. Temperature and relative humidity had no significant effect on the mite population. The highest level of mite infestation was recorded at Sharkia followed by Fayoum and Ismailia Governorates. Mango varieties were differed in their susceptibility to E. mangiferae infestation. Zebda, Taimour, Ewais and Arnaba were the most susceptible varieties, while Mabrouka, Company, Excellent Succari and White Succari were the least susceptible ones. On the other hand Mesk, Geolck and Alphonse varieties showed moderate susceptibility to mite infestation. Buds of some high susceptible varieties possessed a lower values of total carbohydrates and total soluble sugars than some moderate or susceptible varieties to mite infestation. Phenol contents recorded a higher levels in the most of susceptible varieties while a lower levels were found in the most of moderate and low susceptible varieties. The total soluble proteins and amino acids recorded a higher values in some susceptible varieties. The susceptible characteristic was positively correlated with total soluble proteins and amino acids while negatively correlated with the total carbohydrates and total soluble sugars. However the phenol content showed no clear trend. Obtained results also revealed that mango varieties had varying degrees of floral malformation, Company, Alphonse and Geolck were the most susceptible varieties, while Zebda var. was the most resistant one. Statistical analysis showed a negative correlation between the eriophid bud mite and the incidence of malformation disease. Zebda var. harboured the highest number of mites but exhibited the lowest percentages of malformation, whereas the opposite trend was observed with company var