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Globally, vegetable production including tomato is constrained by pests and diseases. The tomato leafminer, Tuta absoluta (Meyrick.), is a major pest of tomato, mainly managed using chemical pesticides. There is a need for integrated pest management (IPM), approaches that are human and environmentally friendly. The study aimed at molecular identification and virulence evaluation of four entomopathogenic nematodes (EPNs) against T. absoluta larvae. The DNA was extracted, sequenced, and phylogeny analyzed. The EPNs virulence was evaluated using the insect baiting technique at different nematode concentrations (0-Control, 100, 150, 200, and 250 infective juveniles/ml of distilled water). Larval mortality data were collected for five days. Molecular identification resulted in nucleotide sequence lengths of 877-895 base pairs (bp). All the isolates were found to be Steinernema species of EPNs. The % similarity of the isolates and their close relatives ranged between 82-100%. The isolates closely matched Steinernema spp. AY230184 (Sri Lanka); AY230186 (Kenya), JN651414 (Ethiopia), and MW151701 (Kenya). The sequences were deposited to Genbank as Steinernema sp. Isolate Kalro 75 (MW150871), Steinernema sp. Isolate Kalro S86 (MW150872), Steinernema sp. isolate Kalro97 (MW150873) and Steinernema sp. Isolate KalroR52 (MW150874). All the EPN isolates were virulent against T. absoluta. Isolate Kalro R52 and Kalro S86 recorded the highest mortality of 76±7.5%; 72±15.0% respectively in the 48 h. There was a significant difference (P < 0.001), between all the isolates and the Control. The four EPNs were virulent and have bio-control potential against, T. absoluta. Research on their virulence against T. absoluta in the field is recommended.

Land-use intensification has a significant influence on occurrence of soil microorganisms. The effect of this phenomenon on Fusarium species is poorly characterized. One hundred soil samples were obtained from 3 replicated land- use types (LUT) in Mwala and Kauti irrigation regions in Machakos County. These included two intensive land-uses under irrigation and rain-fed agriculture and undisturbed lands. Mwala irrigated lands were divided into four blocks based on history of cultivation. Using soil dilution plate technique, 1,546 isolates of Fusarium were recovered and identified into twelve species namely; F. oxysporum, F. solani, F. nygamai, F. equiseti, F. chlamydosporum, F. beomiforme, F. verticillioides, F. proliferatum, F. acuminatum, F. compactum, F. semitectum, and F. merismoides. Fusarium oxysporum was the most abundant and diverse Fusarium species. Fusarium semitectum, F. compactum and F .merismoides had the least distribution being isolated from only one LUT. Fusarium beomiforme and F. acuminatum were recovered from irrigated farmlands only while F. verticillioides, F. proliferatum and F. acuminatum were restricted to disturbed lands only. The difference in abundance of Fusarium between the three LUTs was significant (P = 0.047) with irrigated lands having the highest abundance. Mwala block A had the highest abundance, richness and diversity of Fusarium. Lands with a higher intensity of disturbance had a higher abundance and richness of Fusarium than the less undisturbed lands. This may have severe implication on crop production as most species of Fusarium isolated are pathogenic. Sustainable ways of controlling these potential crop pathogens should be sought.

Belowground biodiversity is one of the key indicators of the sustainability of a land use. This study sought to document the occurrence and diversity of nematode destroying fungi in an area characterized by small scale agriculture in Embu County, Kenya. The study area was divided into six main land use types namely; coffee, fallow, forest, maize/bean intercrop, napier and tea. Nematode destroying fungi were extracted from five soil samples from each of the land uses. A total of 161 isolates of nematode destroying fungi belonging to nine genera and 19 species were isolated and identified. The genera represented were Arthrobotrys, Dactyllela, Dactylaria, Harposporium, Monacrosporium, Myzocytium, Nematoctonous, Paecilomyces and Stylophage. The occurrence of nematode destroying fungi was significantly (P=0.02519) affected by the land use types in the study area. With the exception of Arthrobotrys superb, Dactyllela haptospora, Dactyllela reticulate, Harposporium anguillulae and Monacrosporium ellipsoporum all the other 19 isolated species were not affected by land use types. The highest total mean occurrence of nematode destroying fungi was recorded in maize/bean, followed by nappier, coffee, forest, fallow and tea , in that order. The respective frequency of detection of the fungal species was 7.6, 7.2, 5.0, 4.0 and 3.6. The Shannon index of diversity was highest and lowest at 1.971and 1.177 in the land under maize/bean intercrop and tea, respectively. The species richness was higher in napier, followed by maize bean, coffee, forest and least in tea. Out of the fungi that were isolated, the highest proportion of 23% was from the maize/bean intercrop, while the least 11% was from land under ea. Arthrobotrys oligospora was the most frequently isolated species with a frequency of 24% while Nematoctonus pachysporus had the least frequency of occurrence of 1%. It can be concluded that land use influences the diversity of nematode destroying fungi and nematodes in the soil. More work is needed to determine the efficacy of these indigenous isolates on plant parasitic nematodes.

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.

The occurrence and diversity of nematode destroying fungi in banana based farming systems was investigated in Maragua, Kenya. The ultimate aim of the study is to harness the potential of these beneficial fungi in the control of plant parasitic nematodes, one of the most important banana pests in the region. The study area was stratified into three agro-ecological zones; high, middle and lower from which soil samples were collected. The soil sprinkle method was used to isolate the nematode destroying fungi from the soil. Fifty eight isolates from five genera and six taxa were identified to species level. The species identified were; Arthrobotrys oligospora, A. dactyloides, Monacrosporium cionopagum, Meria coniospora, Dactyllela lobata and Harposporium aungullilae. The results also indicated that, the occurrence of nematode destroying fungi was significantly (2.2 x 10 -16 ) different among the production zones with the frequency of detection decreasing with altitude. The mean frequency of nematode destroying fungi occurrence was 2.8 in the lower zone, while 1.8 and 1.2 was recorded in middle and high zones, respectively. The Shannon diversity index also indicated that, the low ecological zone was the most diverse followed by the middle and the least being the high zone. Monacrosporiun cionopagum was the most frequently isolated of the nematode destroying fungi in the study area with an accumulative frequency of 37.9%. It can be concluded that, soils in the banana production zones are rich in nematode destroying fungi and M. cionopagum is being the most wide spread species.

Land intensification is thought to lead to soil degradation and consequently to loss of soil biodiversity. A study was undertaken to assess the effect of land use on nematode community and nematode destroying fungi in Taita districts, Kenya. Soil samples were collected from land under various uses which were natural forest, plantation forest, tea, coffee, napier grass, fallow, maize/beans intercrop and horticultural crops production. Chemical analysis of the soil properties was done to determine the amount of carbon, nitrogen and potassium in every land use system. The level of carbon declined with land-use intensification with the highest organic carbon level of 7.6% being recorded in soils from the forest while land with high disturbance recorded 1.6% carbon. Similarly, the intensively cultivated soils had lower nitrogen and phosphorous levels compared to the forest. Nematode and nematode destroying fungi were isolated from the soil and identified. Eighty five isolates, distributed in eight genera and fourteen taxa of nematode destroying fungi were identified. The frequency of isolating nematode destroying fungi increased with increased in land use intensity. All the sampled land use types were significantly (P-value = 3.81x10 -07 ) different in occurrence of nematode destroying fungi. The ratios of free-living to plant parasitic nematodes were 5.18 and 0.54 in the natural forest and annual crop production systems, respectively. The frequency of isolation of nematode destroying fungi was positively correlated to abundance of plant parasitic nematodes.