Green Disease Control
그린 병충해방재
Disease Control: Appropriate disaster prevention at the right time is essential to adapt to climate change.
Spring (March - May) Disaster Prevention
Spring pest control is not as important as fall pest control. However, if control is not done properly in the early stages of occurrence, it can become a problem throughout the year, so pay attention to observing early symptoms and apply pesticide immediately upon discovery. In addition, weather conditions, especially rainfall and temperature, about a week before occurrence affect the occurrence, so pay attention to weather changes. As for control of spring blight, use Resolex (500 times diluted, 1ℓ/㎡) and Montseren (1000 times diluted, 1ℓ/㎡) in the form of irrigation twice at one-week intervals. The pathogen mainly lives in the 2-3 cm layer of thatch and invades through the turfgrass, so if the amount of pesticide is insufficient, the pesticide will not come into contact with the fungus and the efficacy will be reduced. Therefore, 1ℓ/㎡ should be applied to ensure sufficient efficacy. When applying preventive spray in spring, the efficacy can be improved by removing the thatch.
▶Spring dead spot
Spring symptoms occur around late March to early April, when Korean grass buds emerge on teeing grounds and fairways. Most of these symptoms appear in the fall of the previous year due to infection by pathogens. Therefore, fall prevention management is very important. However, some infections occur in early spring when spring rain is frequent, so spring prevention is also important. In particular, occurrence is promoted in areas with excessive soil, colored areas of covered greens, and areas with severe dryness, so these areas should be managed to prevent drying out in spring.
Preventive agents are applied twice a week at intervals with a 500-fold dilution, 1ℓ/㎡, and a 1000-fold dilution, 1ℓ/㎡, in the form of a irrigation after removing the spring blight. Minor diseased areas can be completely recovered by May with treatment agents, but large, completely dead diseased areas cannot be recovered until the end of July, so healthy grass should be planted to promote recovery. In addition, areas with frequent outbreaks of spring blight should be identified in detail in the spring to prepare for preventive agents in the fall.
■Large patch
The occurrence of spring rot disease varies somewhat by region. In the southern region, symptoms appear around the end of April, and in the central and northern regions, around mid-May. Therefore, the best time to apply preventive reagents is mid-April in the southern region and early May in the central region. The temperature at which the disease occurs is 15℃~30℃, and the disease starts in early April and gradually increases with the frequency of rainfall, so caution is required during the rainy season in June and July. The disease is promoted by factors such as poor drainage, excessive accumulation of moss, replacement of turf in the affected area, and mechanical work (vertical mowing, aeration), and can also spread due to player spikes.
▶Yellow patch
The incidence increases when spring rain falls under temperature conditions of 10-20℃. In the central region, the incidence period starts from mid-October to March-April of the following year, and in the southern region, it occurs from mid-November to March of the following year. In particular, the incidence is promoted in the case of green covering in winter.
Since this disease is almost impossible to control once it has occurred, preventive control is preferable to therapeutic control. The best time for pesticide control is mid-October to late November and mid-to-late March. It is preferable to reduce the application of nitrogen fertilizer during the outbreak period.
▶Grubs
Damage begins to appear around early April. Effective pesticides include Mephwet and Etop. When applying pesticides, make sure the pesticides can penetrate the soil sufficiently, and it is effective to spray sufficiently before pesticide application or to apply immediately after rain. You can expect an effect if you understand the occurrence of beetles on each golf course and spray pesticides at the right time. It is effective to install baby lights or pheromone traps recommended by the research institute to kill beetles, and to predict the occurrence of adults and apply pesticides at the right time.
▶Pine worm
Spring is the season for transplanting many trees for landscaping. In particular, spring in Korea is often a drought season, so various types of woodworms that attack weakened trees are expected to damage them due to insufficient water supply to transplanted trees, which leads to weakened trees. Woodworms are pests that are difficult to control once they occur, as they attack the pith under the bark and the pith of new shoots, so thorough preventive measures are required to prevent large outbreaks.
Wood borers attack old, transplanted trees, trees transported from long distances, and trees that are weakened due to inadequate post-planting management. Therefore, it is advisable to plant native tree species that grow nearby as much as possible, or trees that have been dug up from areas with similar climate and characteristics.
When transplanting a large tree, be sure to rotate the roots to encourage the development of fine roots. Make the root ball larger so that fewer roots are cut off. Protect the stem by covering it with soil and wrapping it with non-woven fabric. When transporting it over long distances, it is important to cover it with packaging to prevent moisture loss within the tree. Pruning to ensure that the ratio of leaves and branches to roots is appropriate prevents energy loss. Installing stakes or pull ropes should prevent the tree from shaking so that the roots that have formed can take root. After that, management such as irrigation and fertilization at the right time should follow.
In early April, spraying 20ℓ/25g of Mephuric Acid 2-3 times at 5-7 day intervals to the extent that the stems are wet can control overwintering adult moths. Also, spraying the pesticide on the crown in the same way in early June can control new adult moths that move to new shoots and cause damage.
▶Weed control
Weeds that are the target of control in spring include the grass family weed, the sedge family weed, the cycad family weed, the common cudweed, and the Jeju Island weed, and broadleaf weeds such as mugwort and clover.
For annual weed control, pre-emergence soil treatment is effective before weed seeds germinate. The best time to apply this herbicide is early April. Pyributicab (Tough Green), Ronpa, and Prodiamine are safe for creeping bentgrass, so they can be used around the green. In sandy soils with low clay content, there is a risk of phytotoxicity, so it is preferable to apply as a foliage treatment rather than a soil treatment. Furazasulfuron wettable powder (Parandle) is good as a foliage treatment. Herbicide treatment of fairways and tees should be done after sweeping and topdressing.
여름철(7월~9월) 방재
■Tree management
▶Pest Management
Regardless of whether it is a conifer or broadleaf tree, the leaves can lose their vitality and eventually the entire tree can become weak due to the damage caused by sap-sucking pests such as aphids, scale insects, and mites. These sap-sucking pests can be effectively controlled by spraying insecticides and acaricides at the right time.
Aphids: Spray aphid medicine once each in April-May, June-July, and August to easily control them. The way to predict the occurrence of aphids is that in the case of trees adjacent to the work road, the road is wet as if it rained because the excrement has fallen. Also, in the case of trees in the course or rough area, the leaves are shiny or the excrement flows on the leaves, branches, and stems and there is black soot. Apply a partial spot spray to these trees.
Scale insects and mites: Control is somewhat difficult, but the control period is similar to that of aphids, except that additional spraying is required in winter and early spring (February to March). For prediction, if you shake leaves and branches on white paper, red and black insects will crawl around like dust, and the color of the leaves will fade, so that the entire tree cannot maintain its original color. For these trees, spray 2 to 3 types of mites and scale insecticides 2 to 3 times at 10-day intervals to effectively control them.
▶Disease management
In summer, many diseases occur on broad-leaved trees. In particular, the occurrence of red rot is severe in rose family trees such as zelkova, apple, hawthorn, acacia, apple, flower apple, rose, and azalea. Red rot is a disease that occurs in the host exchange between fragrant trees and rose family plants. In fragrant trees, it forms brown spores on stems and branches around April, causing the stems to burst and dry up.
In rose plants, yellow spots and hair-like protrusions called blisters are formed on leaves and fruits in June and July, weakening the tree. For trees that showed these symptoms in the previous year, spray mancozine or polyoxin hydration agent, or lime Bordeaux mixture in April to May and July for sandalwood, and tidiphon hydration agent, phenarihydration agent, or mytan hydration agent in rose plants 2 to 3 times at 10-day intervals to control.
※Acaridae = A collective term for arthropods such as the Platycodon grandiflora, the Platycodon grandiflora, and the Napipodidae. The body length is 1~2mm, and there is no distinction between the cephalothorax and abdomen, making them distinct from spiders. They have four pairs of legs. There are more than 30,000 species worldwide.
※Cedar apple rust = red star disease. A disease that causes red, diseased spots to appear on the leaves of tobacco, pear, and apple trees. It is a heteroparasitic disease that alternates with cedar trees and can be commonly seen in May and June. Hair-like protrusions grow in groups on the back of the leaves and, in severe cases, the leaves fall off early.
