What are the winter pest and disease control measures for flowers and nursery stock?
As temperatures gradually drop, most flower and nursery stock pests and diseases enter the overwintering (or dormant) state in various ways. During this period, various pests and diseases are basically inactive and have limited mobility, making it an excellent season for pest and disease control. Practice has proven that the effectiveness of winter control is directly related to the occurrence of pests and diseases the following year. If winter control measures are effective, they can greatly reduce the occurrence and damage levels of pests and diseases in the coming year, achieving twice the result with half the effort.
I. Cleaning the nursery
The pathogens (fungi) or overwintering eggs of most flower and nursery stock pests and diseases overwinter in dead branches, fallen leaves or weeds within the nursery, and emerge again when conditions are suitable the following year. Therefore, thoroughly clearing and destroying dead branches, fallen leaves and weeds in the nursery during winter and improving sanitation can greatly reduce various pest and disease sources. This has a significant effect on controlling anthracnose, powdery mildew, rust, red spider mites and moths on Chinese roses, roses, chrysanthemums, crabapples and willows, among other flowers and trees.
II. Pruning diseased and pest-infested branches and leaves
Winter pruning is one of the important steps in nursery management. Combined with winter pruning, focus on removing branches and leaves carrying pests and diseases, such as eggs on Chinese roses, roses and other flowers and trees, and scale insects on poplars, willows and flowering shrubs. The pruned diseased and pest-infested branches and leaves should be promptly cleaned up and transported out of the nursery for centralized destruction.
III. Winter plowing and deep turning
Winter plowing and deep turning can subject the larvae, pupae and eggs of underground pests lurking in the soil, such as white grubs, cutworms and mole crickets, to mechanical injury; after being exposed on the surface, they can be pecked and eaten by birds and other natural enemies, and manual capture can also be used when necessary. In addition, deep turning can bury pathogens from the surface soil into deeper layers, while pathogens in the deep layers are turned up to the surface, destroying the suitable living environment for pests and diseases and effectively controlling their occurrence.
IV. Whitewashing for protection
Whitewashing tree trunks and branches can not only effectively prevent frost damage to flowers and trees in winter and improve their disease resistance, but also destroy the overwintering sites of pests and diseases, serving the dual purpose of both frost prevention and pest control. It is especially effective against mites and scale insects that overwinter in the bark. Special attention must be paid to ensuring that quicklime is fully slaked, otherwise it can easily cause burns after being applied to the trunks and branches of flowers and trees.
V. Chemical control
Since various pests and diseases are mostly in a dormant state during winter, chemical control measures in winter can be adopted for those pests and diseases that are difficult to control during their active season. For example, spraying 50-100 times diluted mineral oil emulsion can control scale insects, and spraying 1% Bordeaux mixture 2-3 times in late winter can achieve good control of various diseases such as pear rust and Chinese rose black spot.