Recently, the use of biostimulant substances of different origins has been affirmed. They act differently on the physiological processes of the plant, helping to improve its productive response and resistance to biotic and abiotic stress. Therefore, the response of the wild rocket to two substances known to have biostimulating activity (Azoxystrobin, and a fluid extract of brown algae and yeast), was evaluated. Two experimental trials (Exp 1 and Exp 2) were carried out in the greenhouse. The collected product, in addition to being evaluated from a qualitative point of view, was used for evaluation of shelf life. Exp 1 involved the comparison of two N levels with two Azoxystrobin levels (treated–Azo+, and untreated control). Exp 2 involved the comparison of two N levels, and two biostimulating substances based on Azoxystrobin (Azo+) and on fluid extracts of yeast and brown algae (YBA+), in addition to untreated control. A split-plot experimental design with three replications was used. Azo+ increased marketable yield of wild rocket by 16.8% and enhanced some qualitative features at harvest as the increase in chlorophyll (+17.8%) and carotenoids (+13.5%), and decrease in nitrates (−10.6%), regardless of the nitrogen level. Furthermore, Azo+ increased the shelf life (+2.5 days) of wild rocket stored at 3.5 °C. In particular, Azo+ slowed the loss of chlorophyll (yellowing) and the worsening of odor and visual appearance. As Azoxystrobin is a fungicide effective for the control of some diseases of wild rocket, its use should be promoted as it would offer not only the benefit of disease control but also improved production and shelf life. YBA+ caused an increase in the chlorophyll content (+12.5%) at harvest of wild rocket, but reduced its antioxidant activity (−40%). YBA+ did not cause substantial variations in shelf life with the exception of a slowdown in the degradation of carotenoids. Further research is desirable to evaluate other variables such as the dose and time of application.

Wild rocket (Diplotaxis tenuifolia L. DC) is an emerging vegetable which market requires high-quality standards that can be obtained through appropriate cultivation techniques such as the right level of nitrogen and the application of biostimulant substances. These include strobilurins, marketed mainly as fungicides that can have complementary positive effects on the yield, quality and resources’ use efficiency of many crops. For this reason, a trial in an unheated greenhouse, in Southern Italy, to evaluate the possibility of using Azoxystrobin to improve the production of wild rocket subjected to different nitrogen inputs, was carried out. Two N levels (40 and 140 kg ha⁻¹), Azoxystrobin-based biostimulant (Azo+) and control without Azoxystrobin (Azo−) were compared. The yield, morphological characteristics, nitrogen and water use efficiency (NUE, WUE), antioxidant activity, the content of dry matter, chlorophyll, carotenoids, phenols, and nitrates were assessed. A higher N level resulted in a 16.3% yield increase that was matched by a 12.5% reduction in NUE, 15.8, 7.3, and 16.1% increases in yield WUE (Y_WUE), biomass WUE (B_WUE), and irrigation yield WUE (IY_WUE), respectively, and a worsening of some qualitative characteristics such as a 8.5% rise in nitrates, and a decline by 11.5, 10.1, and 26.1% in the carotenoids, phenols, and antioxidant activity, respectively. Azo+ increased the yield by 10.3%, NUE by 8.9%, and Y_WUE, B_WUE, and IY_WUE, by 13.9, 9.1, and 13.8% respectively. Moreover, Azo+ improved some qualitative characteristics such as total phenols (+9.4%), chlorophyll (+15.2%), carotenoids (+9.7%), and antioxidant activity (+17.4%), while it did not affect the nitrate content. Azoxystrobin can be an additional tool available for farmers to ensure high-quality standards of wild rocket.

The use of biostimulants in agriculture is an emerging technique that can contribute to improved production and resource use efficiency. This research was carried out in southern Italy to evaluate the biostimulating effects of seaweed extract (SW) and azoxystrobin (AZ) on wild rocket subjected to two water regimes (WRs) and three nitrogen levels (NLs), and grown in pots under unheated greenhouse conditions. The following treatments were compared: (i) two WRs: restoration of 100% (WR₁₀₀) and 50% (WR₅₀) of crop evapotranspiration; (ii) three NLs: 0 (N₀), 75 (N₇₅), or 150 (N₁₅₀) kg ha⁻¹ of N; and (iii) three biostimulants (BSs): an untreated control (C), and the application of AZ or SW. This paper reports the effects on N uptake (N_up), N use efficiency (NUE), and water use efficiency (WUE). The following indicators of NUE were assessed: apparent recovery efficiency (RE), internal utilization efficiency (IE), partial productivity factor (PFPn) of N supplied, agronomic efficiency (AE), and physiological efficiency (PE). The following indicators of WUE were assessed: photosynthetic WUE (p_WUE), yield WUE (Y_WUE), biomass WUE (B_WUE), and irrigation yield WUE (IY_WUE). The indicators of NUE were affected differently by treatments. RE was 20% higher with SW. IE was higher with AZ. PFPn increased by 10.4 and 8.1% with AZ and SW, respectively. AE increased by 10.9 and 19.9% after applying AZ and SW, respectively. PE rose by 6.7 and 9.3% after applying AZ and SW. AZ and SW improved p_WUE, mainly under water deficit (interaction of WR × BS). With AZ application, Y_WUE, B_WUE, and IY_WUE were higher by 17.8, 13.8, and 19.3%, respectively, while the application of SW resulted in a smaller increase (9.5–7.7 and 9.9%). SW and AZ were shown to be effective through the moderate improvement of wild rocket’s nitrogen and water use efficiency. The two biostimulants were more effective at improving p_WUE in water deficit conditions, proving to be particularly useful for farmers operating with water scarcity. Therefore, they can provide valuable support to farmers by improving the sustainability of resource use.