Damage levels caused by Capulinia linarosae Kondo & Gullan (Hemiptera: Eriococcidae) on guava crops under two agronomic management practices in the south of lake Maracaibo, Venezuela

Abstract

The objective of the present study was to test the hypothesis of no difference in the level of damage caused by the guava cottony scale Capulinia linarosae (Hemiptera: Eriococcidae) in two guava crops under different agronomic management practices: a crop whose management practices tend to be organic (PUA) was compared with another subjected to chemical methods (PUB). Forty plants in each farm were selected randomly to estimate damage on stems, branches, leaves, and fruits. Levels of damage were statistically different (P<0.0001) between the control methods for stems and branches, but not for leaves or fruits (P>0.05). It was concluded that the magnitude of damage is greater in the crop under chemical control and that agronomic management is a critical factor. Excess of insecticides and incorrect application of pruning causes damage to the plant’s bark and favor the insect proliferation. While the use of a sulfur-calcium broth in PUA regulates pH, favors the effect of other products and promotes the growth of green algae which cover bark crevices avoiding the cottony scale establishment. The excessive use of agrochemicals for weed control in UPB causes soil nudity and kills natural enemies, whereas in the UPA grass layer is clipped at 20 cm on the soil maintaining its moisture and creating habitat favorable to natural enemies.