Rose Care Methods and Rust Disease Prevention Tips
Rose (scientific name: Rosa rugosa), native to China. Belongs to Rosales, Rosaceae, a deciduous shrub, branches with many prickles, odd-pinnate compound leaves, leaflets 5-9, oval-shaped, with marginal prickles. Petals obovate, double to semi-double, flowers purple-red, white, fruiting period August-September, oblate. The rose is native to China. When the rose is grown as a crop, its flowers are mainly used for food and for extracting rose essence oil; rose oil is used in cosmetics, food, fine chemicals and other industries. In daily life, people collectively refer to a series of large, showy-flowered cultivated varieties of the genus Rosa (rose) as roses. In European languages, bramble rose, rugosa rose and Chinese rose all use the same word, such as rose in English and Die Rose in German. The rose is the national flower of the United Kingdom. Today the most common hybrid rose in the world (Rosa hybrida, also known as modern bramble rose or modern Chinese rose) is mainly the product of crosses bred over hundreds of years from many species of the genus Rosa. In particular, it has the traits derived from Chinese rose parentage: a long flowering period, blooming in all four seasons, branches that mainly grow upward, and inflorescences that open prominently at the top of the plant.
Roses like sunlight, are relatively cold-tolerant and drought-tolerant, prefer a ventilated and cool climate, and the suitable growing temperature is 15-25 degrees. Roses are fairly adaptable and not demanding about soil; they grow well and bloom abundantly in fertile neutral or slightly acidic light loam. Before planting, apply decomposed organic fertilizer in the hole as a base fertilizer, and then apply fertilizer four more times during the year, namely: apply a bud-promoting fertilizer once in February-March, and a flower-promoting fertilizer once before flowering; apply a post-bloom fertilizer once after the flowers fade to strengthen the plant's vigor; and apply a wintering fertilizer once when the leaves fall before winter, in a slightly larger amount, which is beneficial for raising soil temperature and helping the plant overwinter safely. For potted roses, decomposed liquid fertilizer once every 10 days is suitable.
Roses are drought-tolerant but not waterlogging-tolerant; if waterlogging lasts a long time, the lower leaves of the plant will drop, and it may even cause the plant to die. Ground-planted roses generally do not need watering at ordinary times; just water appropriately in early spring and during dry seasons. Potted roses can be watered once every 2-3 days, and in hot summer they should be watered every day.
The rose is not only a beautiful flower, but also an economic plant of extremely high value. Its flowers can not only be used as a fragrance ingredient for various preserves, but also for extracting essence and rose oil. On the international market, the value of rose oil is also quite high. When roses bloom, pick the flowers promptly; if you do not pick them, they will bloom only once a year, and the more times you pick, the more times they bloom. Picking is generally done at dawn each day when they open, and it is best to pick those whose buds have just opened in a ring shape; if the flower is fully open and the center is yellow, it can still be picked; if the flower is fully open and the center has turned red, then the quality is poorer.
Roses generally bloom on the current year's branches; regular pruning can make the plant grow vigorously, with abundant flowers and lush leaves, a beautiful tree shape, and can also extend the flowering years. Pruning can be done before the flowering period or during the dormant period.
Rose rust disease is the main disease of roses. It occurs commonly in all parts of the southwest. It is more severe in areas with warm seasons throughout the year and with winter rain and much fog. According to the author's many years of investigation, in some areas of our province the incidence rate is as high as 80%. White-flowered and purple-flowered roses are both infected, causing leaf drop and affecting growth and flowering. It also harms many plants of the genus Rosa. This disease infects leaves, petioles, calyxes and tender stems, first appearing as small yellow spots on the upper side, or orange-red polygonal lesions; in June and July, many apricot-yellow powdery masses appear on the underside of the leaves, and on petioles and young twigs the lesions are yellow tumor-like protrusions. These are its “summer spores”, spread and dispersed by wind and rain. The pathogen is Basidiomycota, Uredinales, Phragmidium rosae-multiflorae; the fungus overwinters as telial piles on diseased parts and on diseased plant residues and fallen leaves.
Prevention and control methods
1. Manual control: promptly remove diseased buds and diseased leaves and burn them in a centralized manner to reduce the spread of the pathogen.
2. Strengthen cultivation management, apply more phosphorus and potassium fertilizer to enhance resistance; pay attention to ventilation and light transmission and drainage to lower the humidity of the surrounding environment and reduce conditions for disease occurrence.
3. Chemical control: from May to August, spray Bordeaux mixture at 1:1:150-200 times every two weeks, and lime sulfur mixture at 0.3 degrees Baumé; the following pesticides can also be selected for spraying: 97% sodium dinitro-o-cresolate 250-300 times solution (add 50-100 grams of soap powder to every 100 jin of pesticide solution), 20% triadimefon (triadimefon) wettable powder 2000 times solution, 30% Ludebao 300-400 times solution, 10% Shigao water-dispersible granules 3000-5000 times solution, 25% Fuxing emulsifiable concentrate 5000-8000 times solution, 30% Tefulin wettable powder 3000-5000 times solution, etc.