Proc. of
Distribution and Incidence of Scab (Sphaceloma
persea) in Avocado (Persea
José Agustín Vidales and José Luciano Morales García
Campo Experimental Forestal y Agropecuario Uruapan, SARH-INIFAP, Apdo. Post. 128,
Abstract.
Scab in the avocado fruit is a disease that affects the producer's
return. It exists throughout the entire avocado zone of Michoacán,
where it is endemic. The objectives if this study were to determine the areas
of greatest incidence of scab as well as its distribution and whether a
relationship exists between the damage caused by thrips
and scab in avocado fruit.
The
working hypothesis was that scab in avocado is found to be distributed all over
the areas where avocado is grown in Michoacán, and
its incidence is greater in semi-hot sub-humid climates. Also, the damage
caused by thrips in avocado fruit facilitates scab
infection.
It
was found that scab in avocado is distributed in the following types of
climates: warm humid, warm sub-humid, semi-hot humid, semi-hot sub-humid,
semi-cold humid, and semi-cold sub-humid.
The
disease occurred with greater severity in semi-cold sub-humid and warm
sub-humid climates. In the semi-hot sub-humid climate, there is a relationship
between the damage caused by thrips and that caused
by scab. This relationship is represented by the model Y = 3072.16 + 0.8774X2
with a coefficient of equal correlation of 0.7488, where Y = percent incidence
of scab and X = percent of damage from thrips.
For
the warm humid climate, the equation is Y = 12.5171 + 1.0887X, with a
coefficient of equal correlation - 0.73. Again where Y = percent incidence of
scab and X = percent of damage from thrips. This
model shows us that for each 1 % of fruit damaged by thrips,
1.0887 percent of fruit is damaged by scab.