Integrated management of plant-parasitic nematodes on guava and fig trees under tropical field conditions

Abstract

Two field experiments were carried out to study the efficacy of different biological control agents in controlling certain plant-parasitic nematode species including Meloidogyne javanica, Tylenchorhynchus mediterraneus, Hoplolaimus seinhorsti, Longidorus latocephalus, and Xiphinema elongatum on guava and fig trees under the tropical field conditions of Jazan region, south-west Saudi Arabia during two successive seasons from Feb. 15, 2016 to Jan. 15, 2017. The evaluated bioagents were used in different integrated management combinations of certain fungal species (Trichoderma harzianum, Verticillium chlamydosporium, and Purpureocillium lilacinum), the bacterium Pasteuria penetrans, some organic amendments (cow manure, compost, and chicken manure), urea 46% as a nitrogenous fertilizer, and the nematicide carbofuran 10G for comparison. Results showed that all the tested treatments gradually decreased (P ≤ 0.05) the population densities of plant-parasitic nematodes on guava and fig trees over the study period. The highest reduction of nematode densities occurred at the end of the experiment. Carbofuran 10G was the most effective treatment in suppressing the nematode densities on guava and fig trees. The most effective management combinations, next to carbofuran 10G, in suppressing the nematode densities in the rhizosphere of guava trees were P. lilacinum + P. penetrans + urea 46%, P. lilacinum + P. penetrans + chicken manure, and T. harzianum + P. penetrans + chicken manure (66.54-69.22% nematode reductions). Correspondent combinations in the rhizosphere of fig trees were P. lilacinum + P. penetrans + cow manure, T. harzianum + P. penetrans + cow manure, P. lilacinum + P. penetrans + urea 46%, and V. chlamydosporium + P. penetrans + urea 46% (54.68-57.17% nematode reductions). On the other hand, nematode population densities continued to increase (P ≤ 0.05) in the rhizosphere of guava and fig trees in the absence of nematode management combinations. All the tested treatments significantly increased (P ≤ 0.05) the number of fruits/tree on guava and fig trees. Treatments which included the combinations of fungal and bacterial parasites along with chicken manure gave the highest numbers of fruits/tree, followed by the treatment with the nematicide carbofuran 10G. Regression analysis showed a significant negative linear relationship between the number of nematodes/kg soil and the number of guava and fig fruits/tree.

Factors affecting success of biological agents used in controlling the plant-parasitic nematodes

“…Apart from some noticeable exceptions, such as Pasteuria spp., which have narrow host range (although this is not always the case; Mohan et al 2012), most BCAs are capable of infecting a wide range of harmful and beneficial nematode species especially in the laboratory (Abd-Elgawad and Vagelas 2015). Yet, different species of BCAs are usually compared singly or in combination with other agricultural inputs in order to identify the best species or combination for managing definite PPN species (e.g., Timper 2014; Hammam et al 2016; Abd-Elgawad 2019b; Dawabah et al 2019). In such cases, the biocontrol processes should be carefully conceived to achieve the best matching between the various attributes of both PPNs and BCAs.…”

Morpho-molecular identification and pathogenicity test on fungal parasites of guava root-knot nematode eggs in Lampung, Indonesia

“…(Swibawa et al 2017). Three reported species of rootknot nematodes attacking guava are Meloidogyne incognita (Razak and Lim 1987), M. Javanica (Dawabah et al 2019) and M. enterolobii (Kumar and Rawat 2018). According to Swibawa et al (2017), all of the RKN attack rates is severe with a second-stage juvenile (J-2) population more than 1000 individuals per 5 g of roots.…”

Relative Efficacy of Some Products Against Meloidogyne Javanica (Treub) Chitwood on Tomato Under Greenhouse Conditions

“…Root-knot nematodes are difficult to control, particularly when using a single control method (Barker et al 1985). Although they showed varying efficacies, different materials and approaches have been used, in Saudi Arabia, to manage root-knot nematodes, including the use of nematicides, resistant cultivars, biological and physical control measures (Al-Hazmi et al 2017, Abdelrafaa et al 2018, Al-Hazmi et al 2019, Dawabah et al 2019. Collange et al (2011) presented a review of methods for managing root-knot nematodes, including organic and inorganic fertilizers, sanitation, and biological control.…”