Phytoseiid mites benefited from organic fertilization by increasing the population of Tyrophagus mites in apple orchards.

This study explores sustainable agricultural practices by examining the role of organic materials in enhancing native predatory mites for controlling spider mites in apple orchards. Developing techniques to conserve indigenous natural enemies is vital for sustainable agricultural production. Phytoseiid mites can control spider mites, which are among the most significant pests in apple production. To conserve phytoseiid mite populations, it is important to identify alternative prey and to determine their role in phytoseiid mite proliferation. We demonstrated that the concurrent use of specific organic fertilizers and coconut husks can increase prey Tyrophagus mites, thereby enhancing phytoseiid mite density. Our research was conducted using sticky traps at the Miyagi Prefectural Agriculture and Horticulture Research Center in Japan. The occurrence of Tyrophagus mites was significantly correlated with the occurrence of phytoseiid mites in 2 years. In laboratory experiments, the use of organic fertilizers increased the density of Tyrophagus mites by 83 × within 4 weeks. Several species of phytoseiid mites were able to lay between 0.25 and 1.03 eggs per day per female by preying on Tyrophagus larvae. A 2-year field survey revealed that the use of organic fertilizers more than doubled the density of phytoseiid mites on apple leaves, likely through promoting Tyrophagus mite proliferation on the ground. These results highlight the potential of organic fertilizers not only to enhance soil nutrients, but also to boost phytoseiid mite populations, thereby contributing to more sustainable apple production.

Plant Growth Inhibitory Activities and Volatile Active Compounds of 53 Spices and Herbs.

The inhibitory activities of the leachates and volatiles from 53 plant species (spices and herbs) were evaluated against lettuce (Lactuca sativa "Great Lakes 366") seedling growth using the sandwich and dish pack methods, respectively. With the sandwich method, parsley (Petroselinum sativum) showed the strongest inhibitory effect on lettuce radicle growth (77%), followed by tarragon (Artemisia dracunculus) (72%). However, caraway (Carum carvi), dill (Anethum graveolens) (seed), laurel (Laurus nobilis), rosemary (Rosmarinus officinalis), and sage (Salvia officinalis) were the most inhibitory species (100% inhibition of lettuce radicle and hypocotyl growth inhibition at all distance wells) in the dish pack method. Cardamom (Elettaria cardamomum) and thyme (Thymus vulgaris) also showed strong inhibitory activity (100% for radicle and hypocotyl growth inhibition at all 41 and 58 mm distance wells). The headspace sampling and gas chromatography-mass spectrometry (GC-MS) analysis identified the main inhibitory active compounds as carvone in caraway and dill (seeds), 1,8-cineole in laurel and cardamom, and borneol in thyme. Both camphor and 1,8-cineole were detected in rosemary and sage, and the total activity evaluation showed that camphor was the major inhibitory compound in rosemary, although both compounds played equal roles in sage.

Identification of safranal as the main allelochemical from saffron (Crocus sativus).

Dried parts of 75 medicinal plant species collected from different regions in Iran were assayed by the Dish Pack Method for volatile allelopathic activity, using Lactuca sativa (lettuce) as the test plant. The highest (60%) inhibition was observed for saffron (stigma of Crocus sativus), followed by Dracocephalum kotschyi, Solanum nigrum and Artemisia aucheri. Safranal was identified as the main chemical by Headspace Gas Chromatography-Mass Spectrometry (HS- GC-MS) analyses of saffron. Moreover, the EC50 of safranal was evaluated as 1.2 µg/L (ppb). This is the first report on allelopathic activity of safranal as a bioactive compound identified from saffron.

Antifungal effects of volatile compounds from black zira (Bunium persicum) and other spices and herbs.

The dish pack method, which measures growth inhibition or promotion effects of volatile compounds on germinating seeds, was applied to measure the antifungal effects of 52 dried samples of spices and herbs against a soil-borne phytopathogenic fungus, Fusarium oxysporum. Black zira showed the strongest effect, followed by cumin and cardamom. Headspace sampling and gas chromatography-mass spectrometry analysis of black zira identified seven volatile compounds, gamma-terpinene, limonene, p-cymene, beta-pinene, alpha-pinene, cuminaldehyde, and myrcene. Among these, cuminaldehyde and p-cymene showed the strongest antifungal activities against F. oxysporum, suggesting roles in the antifungal activity of black zira. The same compounds also showed antifungal activities against another soil-borne phytopathogenic fungus, Verticillium dahliae, and foliar phytopathogenic fungi, Botrytis cinerea and Alternaria mali. The total activity calculated from the concentration of cuminaldehyde contained in black zira and its EC(50) against F. oxysporum demonstrated that cuminaldehyde is the main antifungal compound detected in black zira.