Meloidogyne: The worst nematode pests in greenhouse

Abstract

Covered crop production provides optimized conditions for quality cash vegetables, small fruits and mushrooms, marketable all year around. Presence of host plants, warmth and moisture also promotes intensive development of various pests, including several groups of plant parasitic and mycophagous nematodes. Such pests are often especially persistent and harmful in covered crops, and amongst nematodes the root-knot nematodes (Meloidogyne species) are by far the most harmful ones. They are highly specialized obligate endoparasites causing formation of galls on host plant roots. Several very polyphagous species cause most of the total damage by meloidogyne world wide: Meloidogyne incognita, M. javanica, M. arenaria and M. hapla. Anatomy and function of galled root system are disrupted, and above-ground parts with leaves, flowers and fruits have lower yield and quality. Efficient control of root-knot nematodes is difficult and expensive, because crop rotation does not work and limited choice of pesticides can only suppress population for a short time. Disinfection of infested planting substrate and removal of plants with galled roots contribute to the control. Root-knot nematodes are spread with infested soil and planting material. They cannot infest clean covered crops without assistance of people. Therefore, the most sustainable way of control is to prevent spreading of root-knot nematodes into uninfected greenhouses.

Gajenje biljaka u zaštićenom prostoru je intenzivna proizvodnja, sa visokim troškovima i visoko vrednim proizvodima. Optimizacija uslova za rast i razvoj biljaka tokom čitave godine stvara i veoma pogodne uslove za razvoj raznih štetnih organizama. Neki od njih postali su vremenom naglašeno štetni baš u zaštićenom prostoru. Od nekoliko takvih grupa fitoparazitnih i mikofagnih nematoda, po štetnosti se na globalnom nivou ističu meloidogine (Meloidogyne spp.). To su visoko specijalizovani obligatni endoparaziti i izazivači gala na korenu biljaka. Od 50-ak opisanih vrsta, po štetnosti se ističu vrlo polifagne Meloidogyne incognita, M. javanica, M. arenaria i M. hapla. Usled poremećene građe i funkcije korena, koji je često skoro ceo zahvaćen galama, izdanak slabije raste i formira listove, cvetove i plodove slabijeg prinosa i kvaliteta. Kontrola meloidogina je teška, posebno zbog vrlo ograničenih mogućnosti rutinskog plodoreda i hemijskog suzbijanja. Suzbijanju doprinose svi vidovi dezinfekcije supstrata, kao i uklanjanje ostataka korenja sa galama posle proizvodnog ciklusa. Nematode se unutar i iz zaraženih objekata šire sa supstratom i sa zaraženim rasadom. Kod nas se nedovoljno stručno radi na suzbijanju meloidogina, a posebno se ne pridaje značaj najekonomičnijim i najodrživijim merama - sprečavanju unošenja nematoda u nezaražene objekte, jer one tu ne mogu same doći.