N. Filajdic et al., THE INFLUENCE OF EUROPEAN RED MITES ON INTENSITY OF ALTERNARIA BLOTCHOF APPLE AND FRUIT-QUALITY AND YIELD, Plant disease, 79(7), 1995, pp. 683-690
Two levels of Alternaria blotch (Alternaria mali) intensity and three
levels of European red mite (Panonychus ulmi) populations were establi
shed to study the possible effect of an interaction between mite feedi
ng and fungal infection on disease intensity and fruit quality and yie
ld of apples (Malus x domestica cv. Delicious). The effect of mite fee
ding on disease and yield was most apparent in 1991, when disease seve
rity and levels of mite infestations were higher than in 1992 and 1993
. Disease severity was increased with increased mite densities in more
instances than it was with defoliation and fruit drop. Fruit quality
characteristics such as diameter, weight, firmness, commercial color,
and soluble solids content were not affected to a great extent by incr
eased mite densities although soluble solids content was reduced in ab
out one-half of the tests with a high intensity of Alternaria blotch.