Evaluation of Selected Methods in the Control of Plant Parasitic Nematodes Infecting Carnation

Abstract

Plant parasitic nematodes, whose control options are restricted, continue to cause enormous losses in crop production systems including carnations. This study was carried out with the aim of developing environmentally sound approaches for adoption in the management of phytonematodes affecting carnations. Various organic amendments were evaluated namely sugarcane bagasse, tea and assorted flower composts and molasses, in addition nematophagous fungus Paecilomyces lilacinus (PL plus ® ) and neem (Achook ® ). Meanwhile, a standard chemical nematicide, fenamiphos (Nemacur ® ), was used next to untreated plots were as control. The experiments were carried out under greenhouse conditions. Soil samples were collected before application of the amendments and at 90 and 180 days after treatment. Parasitic nematodes belonging to 16 genera were detected in plots where carnation had been produced under monoculture over several years. The most predominant of the nematodes detected were in the genera Scutellonema, Helicotylenchus and Meloidogyne, with 100, 82 and 100% frequencies of occurrence, respectively. Treatments effects caused a reduction in numbers of plant parasitic nematodes, with the exception of nematodes in the genera Helicotylenchus, Criconema and Longidorus. Galling due to root-knot nematode was reduced by between 53%, in plots treated with sugarcane bagasse, and 69% in those treated with neem. This study has established that application of organic substrates, neem and P. lilacinus reduced plant parasitic nematodes. The materials can be recommended for use in sustainable carnation production systems.

Agricultural nematology in East and Southern Africa: problems, management strategies and stakeholder linkages

“…and RKN have been reported from ornamental plants in ESA (Gowen SR, unpublished) . All three genera are commonly associated with perennial herbaceous ornamentals, a rapidly expanding segment of the floriculture industry in the region, where, for example, carnation ( Dianthus caryophyllus ) is estimated to be grown on more than 500 ha in Kenya, mainly under greenhouse conditions, owing to expanding market demand . Vegetative propagation of many ornamentals may also result in increased spread and distribution of PPN.…”

“…38 All three genera are commonly associated with perennial herbaceous ornamentals, a rapidly expanding segment of the floriculture industry in the region, where, for example, carnation (Dianthus caryophyllus) is estimated to be grown on more than 500 ha in Kenya, mainly under greenhouse conditions, owing to expanding market demand. 17,18 Vegetative propagation of many ornamentals may also result in increased spread and distribution of PPN. Symptoms of nematode infection may range from virtually none to poor growth, stunting, wilting, nutrient deficiency or even death when in combination with secondary organisms.…”

“…Purpureocillium lilacinum strain 251 (PL Plus ® ), organic substrates and one botanical pesticide (azadirachtin 0.15%) used in an experiment to assess PPN control in carnations ( Dianthus caryophyllus ) showed that all treatments reduced PPN; a significant reduction also occurred in RKN egg mass production and root galling with the fungus treatment …”

“…Increasing urbanisation within the region may have contributed to a more commercial approach to horticultural enterprises involving export vegetables, fruits, spices and cut flowers. For example, Kenya, South Africa, Zimbabwe, Zambia, Ethiopia and Uganda have all witnessed the creation of new horticulture industries . These operate in open fields and screen‐houses, with extensive irrigation and use of pesticides and chemical fertilisers.…”

Espécies de Meloidogyne em hortaliças e outras culturas provenientes de áreas periurbanas da África Subsaariana

“…Os colonizadores europeus introduziram a cultura do fumo ( (Talwana et al, 2015;Bridge, 1995). Nematoides dos três gêneros são comumente associados a ornamentais herbáceas perenes, um segmento em rápida expansão da indústria da floricultura na região, em que, por exemplo, cravo (Dianthus caryophyllus L.) ocupa em média 500 hectares no Quênia, principalmente em casa de vegetação, devido às exigências do mercado em expansão (Kimenju et al, 2014;Lnagat et al, 2008). Propagação vegetativa de mudas de plantas ornamentais podem também resultar em aumento da dispersão e distribuição de nematoides.…”