A new disease on greenhouse pepper (Capsicum annuum L.) plants in Culiacan, Mexico with symptoms of chlorosis, wilting and vascular necrosis was observed in 2014. Sixty diseased pepper plants were collected from three different areas of the Culiacan Valley to determine the causal agent of the disease and analyse the potential risk presented by this disease in this region. Fusarium oxysporum was recovered consistently (88% of samples collected) and identified based on cultural, morphological and pathogenicity tests, as well as by PCR amplification and DNA sequencing of the TEF-1α gene. Two pathogenicity tests with 10 monoconidial isolates of F. oxysporum, which were selected randomly from diseased tissues, produced disease symptoms similar to those observed on pepper plants in the greenhouses. Symptoms were different from the typical root rot, wilting and necrosis caused by F. solani and F. oxysporum f. sp. radicis-capsici and instead matched those reported for F. oxysporum f. sp. capsici causing pepper wilt. The results suggest that the causal agent of pepper wilt in the samples analysed was F. oxysporum. This is the first report of pepper wilt caused by this fungus in Mexico, and this disease is a potential threat for pepper production in this region.

Black shading nets are widely used in the protected cultivation of vegetables as a technique for controlling light and temperature, while the colored shading nets, with special optical properties to improve the use of solar radiation, appeared recently in the agricultural plastics market. Light quality transmitted by gray, aluminized, pearl, blue, red and black (control) nets with 30% shade was evaluated, as well as its effects on photosynthetic properties and fruits production of cucumber plants. Treatments (shade nets) were established under a randomized complete block design with four repetitions. The red net transmitted 23.7 and 40.3% more photosynthetic photon flux density (400 to 700nm) and red light (600 to 700nm) and the blue net transmitted 36% more blue light (400 to 500nm) in comparison with the respective transmissions of black net. All nets increased the photosynthetic responses: transpiration, stomatal conductance and CO₂ assimilation, observed in plants grown under black net. Leaf greenness (41.6 SPAD units) and foliar area (90dm²) increased 22.8 and 38.9% with the red net, while the dry weight of leaf (52.5g) increased 21.9% with pearl net. Pearl, red, aluminized and blue nets showed to be viable alternatives because the production of fruit increased in 71, 48, 46 and 46%, respectively, in comparison with the conventional black net (52t ha^-1).

Basal rot is one of the most destructive diseases in onion (Allium cepa) growing regions worldwide. This disease can reduce crop yields by interfering with the absorption and translocation of water and nutrients, causing premature plant death (Delgado et al. 2016). In August 2016, unusual disease symptoms were observed in commercial onion crops (cv. Carta Blanca) within municipality of Angostura (Sinaloa, Mexico). These included yellowish and chlorotic leaves from the tip, progressively developing downward, dwarfing in the plants, soft consistency in bulbs, necrosis in the basal part of the bulb and decrease in roots. Forty symptomatic onion plants were sampled. Tissue from roots and bulbs were plated on potato dextrose agar (PDA) media. Typical Fusarium spp. colonies were obtained from all root and bulb samples. Three pure cultures were obtained by single-spore culturing (Fs05 to Fs07). On PDA the colonies were: abundant white aerial mycelium and light purple pigmentation was observed in the center of ol...