Populations of Oligonychus psidium Estebanes and Baker (Acari: Tetranychidae) correlated with phenological aspects of guava (Psidium guajava L.).

Plant phenology influences over the insects and mites that live upon them, determining along with other factors their emergence and abundance through the productive cycle of the crop. A study was conducted from January to April on eigth plants grown at Centro Frutνcola del Zulia-CORPOZULIA (CENFRUZU), Mara Co., Zulia state, Venezuela to determine the population behavior and distribution of the mite Oligonychus psidium in correlation with the phenological changes of guava plants. The following phenological aspects were monitored two times per month: % vegetative sprouting (%VSP), % blooming (%BLO), % fructification (%FRU), and % developing fruits (%DFR). Simultaneously mites were counted from young leaves, mature leaves and green fruits. Weather conditions were monitored with electronic weather stations, means per each sampling date were provided. Mean mite·plant -1 was higher on mature leaves (84) than on young leaves (46.6) and green developing fruits (3.75). Mite population peaks occurred from January to February 2008 correlated with high %DFR and low %VSP and %BLO. From March to April mite population was low, as well as the %BLO and %FRU. During the first months of the year the populations of O. psidium on mature leaves were correlated with high % DFR, as well as no rain were present during that period, which probably influenced the growth of the fruits. During the season studied the plant phenology could be used to predict the emergence of this pest on guava.