Common diseases and insect pests of Pinus truncatula and their control methods

Common diseases of Pinus tabebuia: clusters of axillary buds and adventitious buds

Symptoms

Axillary buds and adventitious buds grow in large numbers, the internodes become shorter, the leaves turn yellow and become smaller, and clear veins appear. The twigs do not fall off in winter and become shaped like a bird's nest. Severely diseased plants die that year, and mildly diseased plants will die after a few years. The disease is most severe in July and August every year.

Prevention and treatment methods

Ring peeling of diseased branches in spring can prevent the pathogen from transferring and spreading to other parts, thus achieving a preventive and control effect.

Chemical control: Spray 4000 times diluted tetracycline antibiotics in the early stage of the disease.

Introduction to axillary buds

Axillary buds

Axillary buds, a type of lateral buds, specifically refer to fixed buds that grow from leaf axils. Axillary buds are common in ordinary leaves of seed plants. It is rare to see leaves without axillary buds, but scale buds, variegated leaves or the leaves of most ferns generally do not differentiate into axillary buds.

After the new leaf primordium appears from the growth point of the stem apex, the axillary bud primordium of its young leaf primordium will soon differentiate, and usually it will become dormant after a little development. Usually one axillary bud is formed in each leaf axil, but some species may produce more than two axillary buds.

The arrangement of axillary buds on the main axis is, in principle, consistent with the leaf arrangement of the plant, but in trees, because the secondary growth of the stems does not present concentric circles, this arrangement is often slightly skewed.

The main harm of axillary buds is that they cause swelling of the base, affecting the appearance of the plant.

Adventitious buds

In the normal individual development of higher plants, buds generally only grow from certain positions such as the stem tip or leaf axils. Therefore, buds such as terminal buds, axillary buds, and accessory buds that grow in certain positions are called fixed buds.

In contrast, buds that grow from places where buds are not usually formed, such as leaves, roots, or stem internodes, or callus tissue cultured in vitro, are collectively called adventitious buds.