Assessing the performance of different irrigation systems on lettuce (Lactuca sativa L.) in the greenhouse

Growth and Biochemical Composition of Microgreens Grown in Different Formulated Soilless Media

Microgreens are immature young plants grown for their health benefits. A study was performed to evaluate the different mixed growing media on growth, chemical composition, and antioxidant activities of four microgreen species: namely, kale (Brassica oleracea L. var. acephala), Swiss chard (Beta vulgaris var. cicla), arugula (Eruca vesicaria ssp. sativa), and pak choi (Brassica rapa var. chinensis). The growing media were T1.1 (30% vermicast + 30% sawdust + 10% perlite + 30% PittMoss (PM)); T2.1 (30% vermicast + 20% sawdust + 20% perlite + 30% PM); PM was replaced with mushroom compost in the respective media to form T1.2 and T2.2. Positive control (PC) was Pro-mix BX™ potting medium alone. Root length was the highest in T1.1 while the shoot length, root volume, and yield were highest in T2.2. Chlorophyll and carotenoid contents of Swiss chard grown in T1.1 was the highest, followed by T2.2 and T1.1. Pak choi and kale had the highest sugar and protein contents in T2.2, respectively. Consistently, total phenolics and flavonoids of the microgreens were increased by 1.5-fold in T1.1 and T2.2 compared to PC. Antioxidant enzyme activities were increased in all the four microgreens grown in T1.1 and T2.2. Overall, T2.2 was the most effective growing media to increase microgreens plant growth, yield, and biochemical composition.

Life Table Construction under Different Temperatures and Insecticide Susceptibility Analysis of Uroleucon formosanum (Hemiptera: Aphididae)

Simple Summary

Aphids are major crop pests worldwide, and in China, Uroleucon formosanum is a common aphid pest of lettuce. However, there is little basic and applied information on the control of this pest. To obtain the basic information of this pest, a life table of U. formosanum under different temperatures was constructed. Also, the susceptibility of U. formosanum to six common-used insecticides (chlorpyrifos, abamectin, beta-cypermethrin, imidacloprid, nitenpyram, and thiamethoxam) was evaluated. Results showed that U. formosanum was not suitable to a lower temperature (17 °C), and U. formosanum was relatively sensitive to all six test insecticides. These data may help us to develop integrated management strategies for better population control of U. formosanum.

Abstract

Uroleucon formosanum is an important aphid pest of lettuce, but basic information on its biology is scarce. In this study, effects of three constant temperatures (17, 21, and 25 °C, simulating the mean temperature range in greenhouses) on the development and fecundity of U. formosanum were analyzed by constructing a life table. U. formosanum could develop and reproduce under all three temperatures, but the survival rate, development, and fecundity of U. formosanum were affected by temperature. The intrinsic rate of increase was lowest at 17 °C (0.17) and it was significantly less than at 21 °C (0.20) and 25 °C (0.23). Furthermore, U. formosanum had the lowest finite rate of increase (1.19) and the largest mean generation time (20.21) at 17 °C. These results mean that U. formosanum is less adapted to the lower temperatures (17 °C) among these three set temperatures. To screen insecticides for control, susceptibility of U. formosanum to six insecticides including chlorpyrifos, abamectin, beta-cypermethrin, imidacloprid, nitenpyram, and thiamethoxam was evaluated. U. formosanum was relatively sensitive to all six test insecticides. Chlorpyrifos had the highest toxicity to U. formosanum (LC₅₀ = 3.08 mg/L). These data may help to develop integrated management strategies for better population control of U. formosanum.

Effects of Mulching on Early-spring Green Asparagus Yield and Quality under Cultivation in Plastic Tunnels

Mulching significantly increases the crop yield and quality by positively affecting the physical features of the soil. The effect of multiple mulching treatments on soil temperature, yield, and nutrient composition of green asparagus grown in a plastic tunnel was assessed. Two mulch materials: transparent plastic film (PF) and rice husk (RH), were applied and compared with non-mulching treatment (CK). The soil temperatures at the soil surface and 10 cm below it were generally higher in the PF mulch than in the CK during the spring. PF mulch accelerated early spear emergence and growth, which led to harvesting 16 days earlier than in the CK. Under the PF mulch, the early yield of spears increased by 26.6% from January to the end of March, and the annual gross income by 14.8% because of the higher price resulting from the significantly higher marketable spear length and diameter; however, they were reduced in the RH mulch. Most nutrient compositions, such as soluble sugar, ascorbic acid, rutin, flavonoid content, and total antioxidant activity, were significantly increased in the PF mulch treatment. PF mulch might benefit green asparagus production during early spring because of its ability to promote early spear emergence and growth.