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A greenhouse study was conducted to compare the relative efficacy of different approaches to managing on green bean. These approaches included chemical (fumigant, non-fumigant, seed dressing, and seed dip), biological (the egg-parasitic fungus, and the mycorrhizal fungus sp.), physical (soil solarization), and cultural (chicken litter and urea) methods. Accordingly, nine different control materials and application methods plus nematode-infected and non-infected controls were compared. Two important parameters were considered: plant response (plant growth and root galling) and nematode reproduction (production of eggs and the reproduction factor Rf). The results showed that the use of chicken litter as an organic fertilizer severely affected the growth and survival of the plants. Therefore, this treatment was removed from the evaluation test. All of the other eight treatments were found to be effective against nematode reproduction, but with different levels of efficacy. The eight treatments decreased (38.9-99.8%) root galling, increased plant growth and suppressed nematode reproduction. Based on three important criteria, namely, gall index (GI), egg mass index (EMI), and nematode reproduction factor (RF), the tested materials and methods were categorized into three groups according to their relative control efficacy under the applied test conditions. The three groups were as follows: (1) the relatively high effective group (GI = 1.0-1.4, Rf = 0.07-0.01), which included the fumigant dazomet, the non-fumigant fenamiphos, soil solarization, and seed dip with fenamiphos; (2) the relatively moderate effective group (GI = 3.4-4.0, Rf = 0.24-0.60), which included seed dressing with fenamiphos and urea; and (3) the relatively less effective group (GI = 5.0, Rf = 32.2-37.2), which included and sp.

Two outdoor pot experiments were conducted in two consecutive years under outdoor conditions during the wheat growing season in Saudi Arabia to determine the effects of urea and certain compound fertilizers (NPK), compared to the effects of the nematicide fenamiphos on the cereal cyst nematode (CCN), Heterodera avenae, and wheat growth. The results showed that all of the treatments, except the fertilizer diammonium phosphate (DAP), reduced the number of nematode cysts/root system and increased (P ⩽ 0.05) the dry weight of nematode-infected wheat plants. Fenamiphos and urea resulted in the best control, followed by the NPK fertilizers. The combined application of urea and fenamiphos resulted in the most significant effect in decreasing (P ⩽ 0.05) the number of cysts/root system and increasing (P ⩽ 0.05) the growth of nematode-infected wheat plants.

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.

The physiological response of mungbean (Vigna radiata (L.) R. Wilczek) to drought stress and root-knot nematode infection was studied under greenhouse conditions at King Saud University, Saudi Arabia. A randomized complete block Design (RCBD) with factorial arrangement having three replications was used. Treatments included three water deficit (80%, 40% and 20% of field capacity), two mungbean genotypes (Kawmay-1 and VC2010) and two root-knot nematodem, Meloidogyne javanica (Treub) Chitwood, infection levels (noninfected and infected @ 15000 egg/pot). Results showed that water deficit stress and M. javanica infection significantly hampered most of the studied parameters, except shoot water content (SWC). There were highly significant differences in stomatal conductance, shoot dry weight and leaf area among the tested mungbean genotypes. A significant positive correlation among chlorophyll (a and b) contents, stomatal conductance (SC), leaf area (LA) and shoot dry weight (SDW) was recorded. The outcome of the study also revealed that maximum water deficit stress has adversely affected all parameters except SWC, regardless of the genotype or nematode infection status. Similarly M. javanica infection adversely affected the growth and physiological processes of mungbean plants. Moreover, drought and M. javanica infection had synergistic adverse effects on the growth and physiology of mungbean plants. Results also showed that VC 2010 genotype surpassed kawmay-1 in most of the studied characteristics which