结球生菜的正常叶球为圆形，稍平整，叶球紧实。畸形叶球有多种，常见的有不正圆形、直立形、竹笋形、杯形、分球形等。叶球的紧实水平也不一样，有的硬实，有的疏松，有的以至叶球内部中空。
The normal leaf ball of lettuce is round, slightly flat and compact. There are many kinds of abnormal leaf balls, such as irregular circle, upright shape, bamboo shoot shape, cup shape, spherical shape, etc. The compactness level of the leaf ball is also different, some are firm, some are loose, some are even hollow inside the leaf ball.
（1） 发作缘由结球生菜从团棵至第二叶序完成，心叶开端卷抱。
（1） the reason for the attack is that the lettuce is completed from the cluster tree to the second leaf sequence, and the heart leaf begins to curl.
莲座叶继续扩展，心叶加速卷抱构成肥大叶球。结球期叶球构成，喜肥、水充足，结球生菜对温度的顺应性窄，生长适温幼苗期 16?20°C，莲座期18?22°C，结球期白昼20?22°C，夜间是12?15°C。若环境条件不适合，就易构成畸形叶球。不结球是由于早春低温抑止莲座叶肥大，使心叶直立，不进入结球阶段，普通晚熟种类易产生不结球，而早熟种类不结球现象较少；球形叶球膨松，是高温期The rosette leaves continued to expand, and the heart leaves accelerated to form a large leaf ball. In the heading stage, the leaf ball is composed of sufficient fertilizer and water, and the adaptability of the lettuce to the temperature is narrow. In the growth stage, the temperature is 16-20 ° C, in the seedling stage, 18-22 ° C in the rosette stage, 20-22 ° C in the daytime and 12-15 ° C at night. If the environmental conditions are not suitable, it is easy to form abnormal leaf ball. The reason of non heading is that the low temperature in early spring prevents the plumpness of rosette leaves, makes the heart leaves erect and does not enter the heading stage. The common late maturing species are easy to produce non heading, while the early maturing species have less non heading phenomenon. The spherical leaf balls are bulky and are in the high temperature stage结球所致；竹笋球是指进入结球始期，气温忽然升高，构成纵向结长球，疏松，也与多肥、少肥、枯燥等综合要素有关。
Bamboo shoot ball refers to the period when the temperature suddenly rises, forming a longitudinal long ball, loose, and also related to the comprehensive elements such as more, less and boring.
（2） 预防措施
（2） preventive measures
① 选择有机质丰厚、疏松、保水的土壤种植。
① choose the soil with rich organic matter, loose and water conservation.
② 选择适合的播种期，熟习对外界环境条件——温度的请求，然后计算好播种期，设法让结球期规避高温时节，使结球期处于白昼暖和夜间凉快的时期。若结球期遇上日均匀气温超越24°C以上的高温时，可恰当采取盖遮阳网或荫棚降温等措施，与高秆作物或架菜间作，空中覆草，也是克制高温措施之一，可分离采用。
② select the suitable sowing time, get familiar with the request of the external environment - temperature, and then calculate the sowing time, try to avoid the high temperature season, so that the ball period is in the period of warm day and cool night. If the average daily temperature exceeds 24 ° C in the period of heading, measures such as sunshade or shade can be taken properly, intercropping with high stalk crops or vegetables, covering with grass in the air, which is also one of the measures to restrain high temperature, and can be used separately.
③ 定植前分离整地做畦，施用腐熟堆肥。定植后，前期分离浇水分期追肥并停止中耕，使土壤见干见湿，促进根系扩展及莲座叶的生长。中、后期要不时地均勻供给水分，以坚持莲座叶不衰和叶球疾速抱合生长，构成外形正常、紧实的叶球。
③ before planting, separate and prepare land for border, and apply compost. After planting, separate water and apply fertilizer by stages in the early stage, and stop the middle ploughing, so that the soil is dry and wet, and promote the root system expansion and the growth of lotus leaves. In the middle and later stages, water should be supplied evenly from time to time to keep the rosette leaves growing and the leaf ball growing rapidly, forming a normal and compact leaf ball.
④ 合理施用植物激素，激素施用不当时易呈现畸形叶球。
（4） when the plant hormone is applied reasonably, the abnormal leaf ball is easy to appear when the hormone is not applied properly.
⑤ 当叶球紧实时就及时采收，过早采收影响产量，采收过迟叶球内短缩茎伸长，叶球变松，降低质量。
⑤ when the leaf ball is tight, it will be harvested in time. Early harvest will affect the yield. If the harvest is too late, the stem will be shortened and elongated, the leaf ball will become loose, and the quality will be reduced.
⑥ 可以不用人粪尿作追肥。
⑥ it is better not to use human excrement and urine as top dressing.
