Disinfection Methods for Flower Potting Soil and Precautions for Pesticide Use

For the prevention and control of flower pests and diseases, one cannot rely solely on a certain chemical pesticide; rather, different pesticides and dosages need to be used according to the actual conditions of the flower planting site. The following is a summary:

Dimethoate and omethoate: On Rosaceae ornamental plants such as Japanese apricot (Prunus mume), cherry, flowering cherry, flowering peach, elm-leaved spirea (Prunus triloba), Chaenomeles speciosa, apricot, and pear, both can cause obvious phytotoxicity. Dimethoate also causes great damage to Acanthaceae plants such as shrimp plant (Justicia brandegeeana) and coral flower (Pachystachys lutea). If dimethoate is sprayed in June and October, it often causes petals to wither and curl, and leaves, inflorescences, and small branches to fall off, losing their ornamental value.

Dichlorvos: Dichlorvos has obvious phytotoxicity to ornamental plants such as Japanese apricot (Prunus mume), cherry, peach, apricot, and elm-leaved spirea (Prunus triloba). Under normal circumstances, other types of insecticides can be used instead. Dichlorvos also has varying degrees of phytotoxicity to rhododendron, weeping willow, kiwifruit, Chinese scholartree (Sophora japonica), walnut, and cucurbits. When using pesticides to control pests on these plants, one should be very careful and cautious to avoid unnecessary losses.

Rosin mixture: Using rosin mixture in summer has obvious phytotoxicity to persimmon, and in spring and summer it has adverse effects on citrus.

Trichlorfon: Trichlorfon has phytotoxicity to cherry blossom, Japanese apricot (Prunus mume), and the Golden Delicious variety of apple, among others.

Lime sulfur mixture: Lime sulfur mixture has phytotoxicity to Rosaceae plants such as peach, plum, Japanese apricot (Prunus mume), and pear. If lime sulfur mixture is used on these plants, it is best to spray during the leaf-falling season. Pesticide Network reminds that it must never be used during the growing season or the flowering and fruiting period. Lime sulfur mixture also has certain phytotoxicity to kiwifruit, grape, cucumber, and legumes and flowers.

Sumithion: Using sumithion to kill insects in high-temperature seasons has serious phytotoxicity to pomegranate and also causes relatively great damage to cruciferous flowers.

Bordeaux mixture: Bordeaux mixture is sensitive to peach and plum during the growing season. When lower than the double-strength formula, pear, apricot, and persimmon are prone to phytotoxicity; when higher than the equal-strength formula, grape is prone to phytotoxicity.

Chlordimeform: When using chlordimeform to control flower pests, avoid using it on hibiscus (Hibiscus syriacus) and dahlia.

Thiophanate: When controlling pests and diseases of kiwifruit, avoid using thiophanate.

Petroleum emulsion: Petroleum emulsion is prone to causing phytotoxicity to certain peach varieties, so it is best to use it during the leaf-falling season.

In order to avoid pesticides causing phytotoxicity to many ornamental plants, first, targeted switching to other highly effective pesticides without phytotoxicity is necessary; second, the use concentration should be reduced as much as possible; third, do not spray pesticides under high-temperature and high-humidity conditions, as only this way can losses be avoided; in addition, attention should also be paid to the rational mixed use of pesticides. (Wenlan)