Recently, Dora noticed numerous strange “tumors” on the trees along the roadside. Many people mistook them for leaf diseases, but that’s not the case. These are mainly “galls” caused by insect pests. So, what exactly are galls? And how should we handle this situation?
What Are Galls?
Galls are deformed tumors or protrusions. They are formed when various piercing and sucking pests such as aphids, scale insects, and longhorn beetle larvae feed, lay eggs, etc. These activities stimulate plant tissues, accelerating cell division and abnormal differentiation. Galls are a type of gall tumor, which refers to the abnormal development part of the plant body due to insect egg – laying and parasitism. The insects responsible for creating galls are called gall – forming insects.
How Are Galls Formed?
Galls can appear on almost every plant, whether on leaves, bark, trunks, or roots. By blocking the plant’s absorption of water and nutrients and reducing photosynthesis, the plant will become weak and shed its leaves prematurely. In severe cases during the later stage, it can lead to bulging, perforation, leaf lesions, and even plant death. Galls are usually caused by fungi, bacteria, and insects. Among them, insects are the main gall – makers, including aphids, scale insects, weevils, leaf rollers, dipterans, and bees.
What Do Galls Look Like?
Galls come in a wide variety of shapes and sizes. They can range from small lumps to ones larger than baseballs. Some galls are hard, while others are soft. Some have scaly surfaces, and there are even those that are hairy. The internal tissue structures of different galls vary significantly. Some are resinous, some are corky and leathery, and some are densely covered like spider webs.
Prevention And Control Methods
Manual removal: When galls first appear, promptly remove the leaves with galls, clean them, and burn them to prevent the spread of the problem.
Chemical control: Based on the type and stage of gall occurrence, select the appropriate chemical and spray the affected parts.
Early intervention: In the early stages, bacillus thuringiensis or beauveria bassiana can be applied to inhibit the growth of larvae in the soil.