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Relationship determination between Brevipalpus phoenicis (Geijskes) and dothiorella sp. in guava (Psidium guajava L.)

Abstract:

A experiment was conducted to determine the relationship between the mite Brevipalpus phoenicis and Dothiorella sp. Twenty plants from a experimental orchard located at the Centro Frutícola del Zulia, Mara (10° 49' 98"LN and 71° 46' 33"LO) were selected and treated with the purpose of obtaining fruit with and without mite injuries, and inoculated or not with Dothiorella, applying a mitecide (Peropal®), fungicides (Bavistín® and Captan®) and aspersions of Dothiorella innoculum according to each treatment. The fruits were harvested at 14, 21, 28, 35, 49, 56 y 84 days post-anthesis (dpa). Mites were counted at sepals (abaxial and adaxially), peduncles and berry. The presence of Dothiorella was verified placing the fruit on PDA for the growth of the fungi and with histological sections to locate the pycnidia in the apical portion of the fruit. SAS® Program, Tukey's and Frecuency Analysis were used to analyze the data. Dothiorella was present in 1.79% of the fruits inoculated or not with conidia of the fungi, in absence of mites at 84 and 14 dpa respectively. The hystological analysis found one fruit with Dothiorella treated with innoculum and with no mites at 84 dpa. The results could not demostrate if the injuries caused by the mites facilitate the entrance of Dothiorella, since fruits were the mites were present and the inocullum of Dothiorella was applied was not verified on PDA, this coud have happened for unfavourable climatic conditions for the inocullum in the field. Mites fluctuated depending on the treatments and the age of the fruitis and its parts, the highest mean mite was at 35 dpa on abaxial sepals.