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Experimental trials have been carried out in order to evaluate the efficacy of preventative treatments based on plant defense activator products, biocontrol agents, a microbial complex with arbuscular mycorrhizal fungi, and Brassica carinata pellets against Fusarium oxysporum f. sp. lactucae race 1 on lettuce and Fusarium oxysporum f. sp. raphani on cultivated rocket under greenhouse conditions. These products were compared with fungicides known for their ability to induce host resistance (phosethyl-Al and acibenzolar-S-methyl), and with azoxystrobin. Three and four applications of the tested products were carried out on lettuce and rocket seedlings grown in nursery conditions. Treated and untreated plants were transplanted into soil infested with Fusarium wilt agents to obtain an average disease severity (DS) of 65.6–69.2 and of 56.9–62.1 on the untreated lettuce and rocket plants, respectively. The best Fusarium wilt biocontrol was obtained after four applications of Bacillus subtilis Qst713 and with the Glomas microbial complex (42 and 46.7%, efficacy, respectively). B. carinata pellets provided a consistent control when applied 14 days before the rocket and lettuce were transplanted into the infested soil. Acibenzolar-S-methyl, applied at 0.025 g/Liter, showed a DS reduction in F. oxysporum f. sp. lactucae from 36 to 61% and of F. oxysporum f. sp. raphani from 54 to 73%, thus showing statistically similar results to those of azoxystrobin, which was used as a reference (DS reduction from 59 to 65%). Although the Fusarium wilt control provided by such products was not complete in the present experimental conditions, these products can be considered interesting components for an integrated pest management of the Fusarium wilt of leafy vegetables, starting from nursey applications. Moreover, the tested BCAs could become potentially useful, especially for plant monocultures. This study has been produced new information on the effects of potassium phosphite, applied at the nursery level, on reducing lettuce and rocket fusarium wilt. An average efficacy of 69.5% was observed for lettuce, while an average efficacy of 65.2% was observed for cultivated rocket. The good fungicidal activity of the phosphite-based product, coupled with the positive effect on plant biomass, is of special interest.

The downy mildew of basil, which is caused by Peronospora belbahrii, is one of the most devastating basil diseases throughout the world, and management programmes with a limited use of fungicides are necessary to control it. In order to develop efficient integrated disease management programmes, the efficacy of alternative products (calcium oxide, zeolite, orange oil with ascorbic acid, potassium phosphites and bicarbonate), applied in different spray programmes in trials carried out under artificial and natural infestations with the pathogen, has been tested. Various combinations of the treatments were chosen, on the basis of the efficacy of the single products, for further testing in experiments carried out in the presence of natural pathogen infestation and under a reduced crop density. The effect of the tested programmes on downy mildew severity (% of affected leaf area), disease development (AUDPC) and yield (fresh weight of plants) was evaluated. Calcium oxide, K-phosphite and orange oil with ascorbic acid generally provided the most consistent disease control (58%, 40% and 26% efficacy, respectively), when used alone under severe disease pressure, compared to the inoculated control. Spray programmes based on calcium oxide, applied 2 to 4 times, in succession to one application of azoxystrobin, and under a reduced crop density, were the most efficient treatment in the presence of a natural infestation by the pathogen; this IPM programme reduced downy severity as much as 80%, providing the same effect as a conventional chemical programme based on the alternation of azoxystrobin, fluopicolide + propamocarb and mandipropamid.

The production of ornamental plants continues to be a thriving and expanding industry in the United States, Canada, South America, Australia, and Europe, supported by plant industries in many developing countries. Fusarium wilt diseases, however, continue to plague the industry due to imperfections in clean stock propagation systems, latency of disease development, irrigation systems that allow propagule spread, and a low priority placed on breeding efforts towards Fusarium-resistant cultivars of ornamentals. Management requires a multifaceted approach employing cultivar resistance as well as cultural, biological, and chemical strategies. Ignorance of the sources of inoculum and how it is spread has allowed many missed opportunities for preventing Fusarium wilt diseases. When the disease has become established in a production system, many approaches for achieving suppression have been explored, but most have not met the high standard for a zero disease threshold demanded by the industry. The following review was designed to highlight management studies that have advanced our knowledge of how to minimize Fusarium diseases and to indicate areas where additional research and technological development are needed.

A new leaf spot of wild rocket (Diplotaxis tenuifolia), caused by the seed transmitted pathogen Plectosphaerella cucumerina, is causing severe losses on this crop. Disease management is complicated, as few chemicals are registered for use on rocket. Four experimental trials using fungicides, resistance inducers, and a biocontrol agent against P. cucumerina were carried out on two cultivars of wild rocket, under greenhouse conditions, in order to evaluate the efficacy of the different treatments. In the presence of a disease severity ranging from 5.8 to 26.6 in the control plots of wild rocket (cvs Grazia and Rucola selvatica), one foliar application of azoxystrobin, boscalid alone or combined with pyraclostrobin provided a significant reduction in disease severity, compared with the untreated control, at values ranging between 48.5% and 84.8%. The phosphites-based products and acibenzolar-S-methyl provided the most constant results when applied in three treatments, with a disease severity reduction ranging between 34%–82% and 45%–70.3%, respectively. The highest disease reduction in disease severity was observed by using two sprays of mandipropamid at 18.7 mL/100 L with an efficacy ranging between 64% and 92%. Among the copper-based products, the most effective treatments compared with the untreated control plants were the copper hydroxide and terpenic alcohols. Thiram provided a significant reduction in disease severity compared with the untreated control plants at values ranging from 53% to 78%; however, the plants generally did not improve in biomass compared with the untreated control. The most effective treatment in terms of disease severity reduction did not always provide a better response in plant biomass. Streptomyces griseoviridis provided only a partial, but consistent, reduction of leaf spot on wild rocket when applied in three treatments at seven day-intervals, with results statistically different from those observed in the untreated control plants. Considering the difficulty in reaching a complete disease management level against P. cucumerina, an integrated approach should be considered.

A mixture of 1,3-dicloropropene 60.5% w/w and chloropicrin 33.3% w/w (Telone C35 EC) may be registered in Italy for soil drip fumigation. Five experiments on greenhouse tomatoes in Northern, Central and Southern Italy compared the effectiveness of this mixture in comparison with methyl bromide to find the optimum application rate in soils infested by Fusarium oxysporum f.sp. lycopersici, F. oxysporum f.sp. radicis lycopersici, Sclerotium rolfsii, Meloidogyne javanica and M. incognita.Its efficacy against F. oxysporum f.sp. radicis lycopersici and M. incognita was confirmed when applied to soils at 100, 200, 300 and 400 l/ha (132.4, 268.4, 402.6 and 536.8 kg/ha) under gas-tight films with 15–45 mm of application water (900–1200 mg Telone C35 EC/l). In sandy soils, with slight F. radicis lycopersici infections and with heavy nematode (M. incognita) attacks, the mixture, drip applied at 900 mg/l during late summer (fumigation: late summer; transplant: late-summer/autumn; last harvest: early spring), performed well up to 132.4 kg/ha (100 l/ha).In sandy loam soils with slight F. radicis lycopersici infections and severe infections of F. lycopersici and galling nematodes (M. javanica), 268.4 kg/ha (200 l/ha) of the mixture applied at 900 mg/l as a drip provided yields similar to those of methyl bromide treated plots both in spring and summer cycles. In sandy loam soils, the diseases (F. lycopersici, F. radicis lycopersici) were controlled at rates 268.4 kg/ha (containing 90 kg/ha of chloropicrin), but the mixture was ineffective against Sclerotium rolfsii occasionally observed in sandy loam soils. In both sandy and sandy loam soils, no significant relationships were found between the rates of mixture applied (132.4, 268.4, 402.6 and 536.8 kg/ha) and the degree of nematode infestation.

The strobilurins, azoxystrobin, kresoxym-methyl and trifloxystrobin, were tested in experimental trials carried out in the growth chamber or glasshouse against Fusarium wilts of carnation (Fusarium oxysporum f. sp. dianthi), cyclamen (F. oxysporum f. sp. cyclaminis) and Paris daisy (Fusarium oxysporum f. sp. chrysanthemi), in comparison with benomyl and in some experiments prochloraz. The three strobilurins controlled Fusarium wilt on carnation when applied at transplant at 1–2 g/m2 as soil drenching. Azoxystrobin, at 250 mg/l of medium controlled also Fusarium wilt on cyclamen and on Paris daisy. Kresoxim methyl at 250 mg/l controlled Fusarium wilt on cyclamen but it was phytotoxic; at the same dosage it was not effective on Paris daisy. Trifloxystrobin was only partially or not effective in controlling Fusarium wilt on cyclamen and Paris daisy. Particularly kresoxim-methyl caused chlorosis and plant stunting. This study shows the high efficacy of azoxystrobin against Fusarium wilts of three important ornamental crops. Azoxystrobin provided control similar or better to those shown by benomyl, applied at higher dosages in all trials.

Soil solarization, carried out in raised concrete benches in two subsequent years, proved very effective against Fusarium oxysporum f. sp. basilici and Rhizoctonia solani on basil. The temperatures reached in mulched benches at 5 and 15 cm depth were respectively 48 and 45 °C. The efficacy of soil solarization against Fusarium wilt was generally not improved by combining with strains of Fusarium spp. antagonistic to F. o. f. sp. basilici.