The integrated management of bud rot disease and Phytophthora palmivora in oil palm Colombian Oil Palm Research Center – Cenipalma, Colombia

Coconut leaf rot in association with root (wilt) is widespread in southern districts of Kerala, India. The disease complex has spread to northern districts of the state and also adjacent districts in Tamil Nadu. Where as the root (wilt) is a systemic infection (due to phytoplasma) the leaf rot is a foliar syndrome due to fungi (Colletotrichum gloeosporioides, Exserohilum rostratum, Fusarium spp.). Occurrence of leaf rot has been related to the incidence of root (wilt) and its appearance in young palms remained a matter of contention as to which disease precedes the other. Leaf rot lesions do occur on leaf petiole/mid-vein/mid-rib even as the disease lesions are known to be common on lamina (spindles). Investigations brought out that in majority of leaf rot affected young palms (2-5 years old) the flaccidity symptom of root (wilt) could be also discerned. In lesser number of affected palms, the other symptoms of root (wilt), yellowing and marginal necrosis, were also visible. As such, in 88.5% of leaf rot affected young palms one or the other symptom of root (wilt) has been recorded irrespective of season. C. gloeosporioides, E. rostratum and other fungi were found both in lamina and petiole lesions in different months. C. gloeosporioides was detected from petiole and lamina tissues in all the months, followed by E. rostratum, Fusarium spp. etc. C. gloeosporioides was isolated from these parts in more numbers and consistently during January-December. E. rostratum appeared erratically. Aggressiveness of C. gloeosporioides during months of wet season was confirmed. Fusarium spp. was isolated predominantly from these parts in dry months (January-May). Knowledge on occurrence of leaf rot in young palms in relation to root (wilt) and dynamics of leaf rot pathogens in leaf parts among months/seasons of year (in inoculums build-up, spread and dissemination) are important in the context of integrated management of root (wilt)-leaf rot complex.

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Aktivitas Bakteri Kitinolitik dari Cangkang Perna viridis sebagai Antifungi Phytophthora palmivora Penyebab Penyakit Busuk Buah Kakao (Theobroma cacao L.)

bionature ◽

10.35580/bionature.v18i2.6139 ◽

2018 ◽

Vol 18 (2) ◽

Author(s):

Ulfia Nurul Khikmah ◽

Muhson Isroni Isroni ◽

Anisa Maulidiya

Keyword(s):

Enzyme Activity ◽

Phytophthora Palmivora ◽

Perna Viridis ◽

Bacterial Isolates ◽

Chitinolytic Enzyme ◽

Chitinolytic Bacteria ◽

Agriculture Sector ◽

Rot Disease ◽

Bacterial Characterization ◽

Physiological Characters

Abstract. The emphasis on the growth of Phytophthora palmivora was important in order to reduce Pod Rot Disease of cacao (Theobrorna cacao L.) which could harm agriculture sector. Some bacteria had chitinolytic enzyme activity that is potentially used as an antifungal against Phytophthora palmivora, because the cell wall of the fungi composed of chitin. The purpose of this research was to know chitinolytic bacteria from Perna viridis shell which had higher activity of chitinase enzyme, the amount of chitinase enzyme activity of each selected isolate, and to know the effect of chitinolytic bacterial isolates from Perna viridis shell to reduce the growth of Phytophthora palmivora. The bacteria were isolated from Perna viridis shell at Depok Beach, Kretek, Bantul, Yogyakarta. This research was an explorative research which include bacterial characterization and experimental research which include antagonistic test of chitinolytic bacteria against Phytophthora palmivora. The chitinolytic bacteria was isolated using selective chitin agar medium by pour plate method and then screening the isolates that had chitinase enzyme activity by measuring the enzyme activity of each bacterial isolates by spectrophotometric method. Selected bacterial isolates were characterized by macroscopic, microscopic and physiological characters. The bacteria that had been selected tested for their ability to reduce the growth of Phytophthora palmivora by Kirby Bauer modification method. The result showed that there were 10 isolates that had chitinase enzyme activity which two selected isolates had the higher chitinase enzyme activity. There were 7D and 6B isolates. The isolate 7D had 1,258 u/ml chitinase enzyme activity and isolate 6B had 1,212 u/ml chitinase enzyme activity. The result of chitinolytic bacterial antagonist test on Phytophthora palmivora growth showed that both bacterial isolates were potential to antifungal Phytophthora palmivora and showed a real effect in inhibiting the growth of Phytophthora palmivora with significance value < 0,05.Keywords: Chitinolytic Bacteria, Perna viridis, Phytophthora palmivora

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