INFLUENCE OF CITRUS LEAF NUTRITION ON SURVIVORSHIP, SEX-RATIO, AND REPRODUCTION OF EUSEIUS-TULARENSIS (ACARI, PHYTOSEIIDAE)

Citrus trees, Citrus sinensis (L.) Osbeck, grown in pots were fertiliz ed weekly for 3 mo after grafting with 1, 1/10, 1/100, or 1/1,000x con centrations of a fertilizer solution. of the predaceous mite, Euseius tularensis (Congdon), were placed with ice plant, Malephora crocea (Ja cquin) pollen on excised leaves, and no differences in survivorship or ser ratio were found during the Ist or 2nd generations of rearing. Du ring die 2nd generation, however, egg production by E. tularensis rear ed on leaves from the Ix fertilized trees was higher both on the Ist d df oviposition and throughout most of the lifespan of the females com pared with the other treatments. As fertilizer concentration decreased , fewer total eggs were deposited by E. tularensis females. Leaf analy ses revealed significant, decreasing linear responses in concentration s of N, K, Mn, and Zn in the leaves as fertilizer concentration was de creased. Decreasing concentrations of N and Mn were significantly corr elated with decreasing reproduction in the predaceous mite. These data suggest that E. tularensis feeds on leaf sap and its reproductive ten tial is influenced by the nutritional status of the citrus tree.