The mite Brevipalpus phoenicis, vector of citrus leprosis, is a polyphagous species and has a wide host range in citrus orchard, where it can maintain and/or increase its population. The objective of this study was to evaluate some relations between the mite B. phoenicis over horseweed plants (Conyza canadensis) for different heights. To determine the oviposition and survival of B. phoenicis, an experiment arranged in a complete randomized statistical design was carried out, with five treatments and twelve replications. The treatments established were: (1) plants smaller than 20 cm, (2) plants with height between 21 to 50 cm, (3) plants with height between 51 to 100 cm and (4) plants taller than 101 cm, as well as (5) branch sections of the orange plant. Ten female adults of B. phoenicis were transferred to each section. Survival and oviposition were evaluated 120 hours after transference. The mite was also photomicrographed using a scanning electron microscope. Taller horseweed plants were biased toward B. phoenicis' survival, compared to lower plants. However, the number of laid eggs was not different according to horseweed height. Based on the photomicrography, it was possible to verify B. phoenicis 'preference for feeding on the trichome base located on the stem surface of the horseweed. This is possibly justified based on the increased cell turgor in this part. Therefore, the large number of trichomes present in horseweed plants can promote higher survival range and development of B. phoenicis , being thus used as an alternative host, what may contribute to the spread of this mite population and, consequently, of leprosis over the citrus orchards.
citrus culture; oviposition; CiLV virus
