Researches on biological control possibilities against citrus diseases caused by <em>Phytophthora citrophthora </em>(Sm. et Sm.) Leonian.

Abstract

Researches had been carried out during 1987-1993 in Antalya Citrus Research Institute. 121 soil samples were collected from the citrus orchards and their surroundings in İçel, Antalya and Muğla provinces. The zoospore germination was tested by agar-disc method and mycelium development was tested by soil-agar-cellophane method. Four soil samples that are suppressive against P.citrophthora were determined. Among 602 isolates that were isolated from these 4 soil samples; 3 Bacillus spp., 5 Actinomycetes, 10 fungi (Trichoderma viride, T.hamatum, T.harzianum, T.aeroviride and T.pseudokoningii), 3 Penicillium spp., 1 Aspergillus sp. and a fungus that was contaminated from laboratory were selected as most effective antagonists by dual culture method in petri dishes tests. The fruits and saplings of Kara Limon variety were used at in vivo experiments. At first the pathogenicities of these antagonist against lemon fruits and shoots were tested. T.pseudokoningii, Penicillium spp. and Aspergillus sp. were found as pathogens of lemon fruits. For this reason they were eliminated from fruit experiments but they were used at gummosis studies. The moving zoospores of the pathogen were used at both fruit and stem studies. The host wasn't wounded. The spore suspensions of the antagonist were applied  24 hours before the pathogen application by dipping and spraying methods. As a result of the studies carried on against brown rot of fruits, Actinomycetes were 58.3-83.4%, Bacillus spp. 50% and Trichoderma spp. 50.0-58.3% effective. As to against gummosis it was found that Bacillus subtilis 50.1%, Actinomycetes 50.1% and Trichoderma 33.33% effective.

Keywords

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Turunçgillerde <em>Phytophthora citrophthora </em>(Sm. et Sm.) Leonian'a karşı biyolojik mücadele olanakları üzerinde araştırmalar.

Öz

Araştırma l987-l993 yıllarında Antalya'da yürütülmüştür. Phytophthora citrophthora (Sm. et Sm.) Leonian'ya karşı antogonist mikroorganizmaları elde etmek amacıyla İçel, Antalya ve Muğla illeri narenciye bahçeleri ve çevresinden toplanan toprak örneklerinden 4 baskıcı toprak saptanmıştır. Bu 4 topraktan elde edilen 602 mikroorganizma izolatı içerisinden en etkili 3 Bacillus spp., 5 aktinomiset, 10 fungus (Trichoderma viride, T.hamatum, T.harzianum, T.aeroviride, T.pseudokoningii, 3 adet Penicillium spp., 1 adet Aspergillus sp. ve LabF-1 kod no'lu fungus) elde edilmiştir. Bu etmenlerin antagonistlik etkileri petri kablarında yürütülen ikili kültür testleriyle ortaya konmuştur. Çalışmalarda kara limon (Citrus limon Burm.) meyve ve çöğürleri kullanılmıştır. Önce bu antogonistlerin limon ve meyve sürgünlerine patojen olup olmadıkları saptanmıştır. T.pseudokoningii, Penicillium spp., Aspergillus sp. meyvede patojen bulunmuş ve meyvelerde görülen kahverengi meyve çürüklüğüne karşı antagonist uygulaması denemelerinden çıkartılmıştır. Gövde zamklanması karşı yapılan çalışmalarda ise tüm izolatlar denenmiştir. Kahverengi meyve çürüklüğüne karşı yapılan çalışmalarda, P.citrophthora'ya karşı aktinomisetler %58.3-83.4, Bacillus'lar %50, Trichoderma  spp. %50.0-58.3 etkili olmuştur. Gövde zamklanmasına karşı ise, Bacillus subtilis ile %50.1, Aktinomiset ile %50.1 ve Trichoderma spp. ile %33.33 etki elde edilmiştir.

Anahtar Kelimeler

• citrus; biological control; antagonist; Phytophthora citrophthora