Background: The occurrence of calcium (Ca)‐related disorders is common in tomato production and may be due to factors such as excess nitrogen (N) fertilization. Thus, Ca sprays are often applied as preventive measure to avoid the occurrence of blossom‐end rot. In addition, evidence indicates that Si can act beneficially on tomatoes and relieve Ca deficiency. Aims: We aimed to verify the effects of Ca‐EDTA and Si application on tomatoes experiencing moderate Ca deficiency. Methods: Tomato plants were grown in nutrient solutions with Ca sufficiency (+CaR) or Ca deficiency (–CaR) or under conditions of –CaR plus 25 mM Ca‐EDTA shoot sprays (–CaR +CaS), –CaR plus 7.1 mM Si shoot sprays (–CaR +SiS) or –CaR +CaSiS, with a total of nineteen sprays being supplied after anthesis, per foliar treatment. Results: Plants grown under –CaR had smaller leaves and fruits, and new shoots were deformed. Plants that were sprayed with Ca‐EDTA and Ca‐EDTA plus Si in the same solution developed more blossoms than those grown without Ca; however, they showed chlorosis and necrosis on the edges of older leaves, i.e., Ca‐EDTA was toxic. However, the plants sprayed with Si alone were the most similar to control plants, showing only deformations in the younger leaves. Conclusion: Ca‐EDTA at 25 mM sprayed twice a week after anthesis, totaling 19 sprays, caused toxicity in MT tomatoes. Sodium silicate (7.1 mM Si) sprayed twice a week after anthesis, totaling 19 sprays, made MT tomatoes less sensitive to Ca deficiency. Thus, we highlighted the potential of Si spraying to alleviate the slight Ca deficiency, which is relatively common in horticulture.

The use of silicon (Si) has a physical barrier effect on plant tissues, decreasing nematode infection in different crops. Notwithstanding, research on lettuce crop is lacking, especially regarding the chemical mechanisms of action of this bene cial element. Therefore, this study evaluates the effect of Si supply on lettuce plants infested with 0, 6000, and 12000 eggs and second stage juveniles of M. incognita, both in the absence and in the presence of Si (2 mM) in the nutrient solution. Silicon increases phenolic compounds and ascorbic acid, reducing the M. incognita population and decreasing oxidative stress. It also increases chlorophyll index and the quantum e ciency of the photosystem II (FV/FM), favoring the growth and production of lettuce plants. The use of Si decreased the number of nematodes and affected their reproduction, decreasing the number of eggs and galls in the roots of lettuce plants, being yet another sustainable alternative for the control of M. incognita. The Si bene t would be due to the combined effect of the physical barrier and the chemical action from the increase in phenolic compounds and ascorbic acid in plant tissues, improving the physiological aspects of plants. Key MessagesThe Lactuca sativa is a crop susceptible to the attack of root-knot nematode.The Si strengthens the defense system of this plant against incognita.Si has an effect on increasing the rmness of tissues acting as a physical barrier in control of incognita.Si supply decreases the reproduction rate of incognita. The Si a sustainable alternative, in control of root-knot nematode since its use can reduce applications with nematicides.

The use of silicon (Si) has a physical barrier effect on plant tissues, decreasing nematode infection in different crops. Notwithstanding, research on lettuce crop is lacking, especially regarding the chemical mechanisms of action of this beneficial element. Therefore, this study evaluates the effect of Si supply on lettuce plants infested with 0, 6000, and 12000 eggs and second stage juveniles of M. incognita, both in the absence and in the presence of Si (2 mM) in the nutrient solution. Silicon increases phenolic compounds and ascorbic acid, reducing the M. incognita population and decreasing oxidative stress. It also increases chlorophyll index and the quantum efficiency of the photosystem II (FV/FM), favoring the growth and production of lettuce plants. The use of Si decreased the number of nematodes and affected their reproduction, decreasing the number of eggs and galls in the roots of lettuce plants, being yet another sustainable alternative for the control of M. incognita. The Si benefit would be due to the combined effect of the physical barrier and the chemical action from the increase in phenolic compounds and ascorbic acid in plant tissues, improving the physiological aspects of plants.