Detailed Explanation of Key Techniques for High-Yield Cultivation of Chinese Gall
Chinese GallChinese gall is an insect gall formed by certain aphids of the family Pemphigidae parasitizing plants of the genus Rhus in the family Anacardiaceae. It has the effects of reducing swelling, disinfecting, preserving, stopping bleeding and relieving pain. Chinese gall tannin is widely used in metal anti-corrosion, extraction of rare metals, dyeing and color fixation of synthetic fibers, the food industry, the pharmaceutical industry, medical hygiene and chemical analysis. According to different summer host plants, it can be divided into: horned gall, round-horned gall, red gall flower, etc. parasitic on Rhus chinensis; belly gall parasitic on Rhus punjabensis var. sinica and Rhus potaninii; and Pistacia chinensis gall parasitic on Pistacia chinensis.
Morphological characteristics
1. Chinese gall aphid autumn migrant aphid (winged parthenogenetic aphid): body elongated oval, length 2.1 mm, width 0.74 mm, grayish black. Body surface smooth, vertex with longitudinal striae, dorsum of head with obvious transverse reticulation. Antennae 5-segmented, segment 3 longest, rostrum short. Legs 3 pairs, with imbricate striae. Abdomen slightly conical, abdominal tube absent. Cauda cake-shaped and smooth, anal plate semicircular. Wings 2 pairs, transparent; forewing with 4 oblique veins, media not forked, pterostigma elongated, sickle-shaped, extending to wing apex; hindwing with 2 oblique veins. Sexual aphid: female aphid body oval, light brown. Newly born body length 0.5-0.56 mm, width 0.26-0.27 mm. Male aphid body elongated oval, narrower than female aphid, pale green, newly born body length 0.39-0.45 mm, width 0.17-0.21 mm. Mouthparts of both female and male aphids degenerated. Fundatrix: body elongated oval, dark brown, newly born body length 0.26-0.38 mm, width 0.13-0.19 mm.
2. Summer host plants. Rhus chinensis is a deciduous small tree or shrub, 2-10 m tall. Bark grayish brown, branchlets densely covered with rusty pubescence. Pinnately compound leaves, alternate. Paniculate inflorescence, much branched; female inflorescence shorter, flowers greenish white; male flowers, calyx lobes long ovate, petals obovate-oblong. Infructescence erect, drupe oblate, red when mature.
Rhus potaninii is a deciduous tree, 5-8 m tall. Bark rough, grayish brown, branchlets glabrous. Odd-pinnately compound leaves, alternate, leaflets 7-9; paniculate inflorescence terminal, flowers white; infructescence pendulous, drupe subglobose, red when mature.
Rhus punjabensis var. sinica is a deciduous tree or small tree, bark grayish brown, branchlets slightly pubescent. Odd-pinnately compound leaves, paniculate inflorescence terminal, densely covered with fine pubescence; flowers small, white, anthers purple; calyx 5-lobed, petals 5; infructescence pendulous, drupe subglobose, dark purplish red when mature, densely covered with pubescence, seeds small.
3. Winter host plants. Plagiomnium maximoviczii grows in tufts, body short and small; stems erect, base with many rhizoids, apex with clustered leaves. Leaf blades elliptic-lingulate, with several transverse undulations, apex rounded and blunt. Dioecious; sporophytes mostly in clusters; capsules flat or pendulous, ovate-oblong; operculum conical.
I. Reasons for the formation of Chinese gall
Chinese gall is the general term for insect galls formed by gall aphids parasitizing plants such as Rhus chinensis. When plants such as Rhus chinensis sprout young buds in early spring, the fundatrix pierces the young cells of the host with its piercing-sucking mouthparts on the leaf wings or the main axis of the compound leaf, and secretes saliva containing a large amount of enzymes that penetrates into the cambium, stimulating cell division, increasing their number, and protruding toward the upper surface of the leaf, forming a gall prototype. After the fundatrix grows up inside the gall, it begins to give viviparous birth to the fundatrigenia generation, the population gradually increases, stimulation also continuously increases, and the gall gradually enlarges. The gall develops slowly in the early stage and rapidly in the later stage. The prototype gall is pale onion-green, continues to develop into dark green, and turns red or rose when mature.
II. Establishing a Chinese gall base
1. According to the reasons for the formation of Chinese gall, we can establish a Chinese gall production base in places where the growth conditions for Chinese gall are suitable. Choose semi-shaded hillsides with dense lower-layer weeds and abundant moss plants, both banks of rivers, and places where a small amount of Chinese gall can be naturally produced in the upper layer, and plant Rhus chinensis, Rhus punjabensis var. sinica and Rhus potaninii in large quantities.
2. Protect winter hosts. Many moss plants are winter hosts of gall aphids, and their growth directly affects the number of migrant aphids the following spring. Therefore, we should protect and cultivate moss plants in large quantities under Chinese gall forests such as Rhus chinensis, Rhus punjabensis var. sinica and Rhus potaninii, creating overwintering conditions for gall aphids.
3. Retain gall seeds. Chinese gall is formed by gall aphids parasitizing and reproducing on gall trees. Therefore, when harvesting, we should pay attention to retaining seeds, leaving 1-2 large galls per tree for seed use. Let the galls burst naturally, and the gall aphids will naturally migrate to moss host plants to overwinter, then fly back to the gall trees in spring to parasitize and reproduce, producing galls.
III. Harvesting and processing of Chinese gall
Chinese gall can be harvested when it gradually changes from green to onion-green or onion-white, and the sun-facing side of the gall turns bright red or slightly red. Mature galls are large, have high tannin content and good quality, so they should be harvested at the right time. The freshly harvested galls should be sun-dried or oven-dried in time before being sold.