Large-leaved boxwood is an evergreen shrub that is one of the most commonly used green plants in the streets of towns and in the green spaces of parks, squares, unit courtyards and communities. In the process of planting large-leaf boxwood, some diseases and insect pests often occur, and how to effectively control the diseases and insect pests of large-leaf boxwood is the key to improving the production of large-leaf boxwood. Some diseases and insect pests encountered by large-leaf boxwood in the growth process, such as large-leaf boxwood powdery mildew, large-leaf boxwood brown spot disease, large-leaf boxwood silk leaf borer, Japanese turtle wax, etc., because the conditions of the corresponding growth environment of this tree are relatively large, and there are more extensive management methods, it also has a more serious occurrence of diseases and insect pests, which seriously affects the landscape of urban greening. Some of the diseases and insect pests encountered by the large-leaved boxwood and the corresponding control methods are introduced as follows:
<h1 class = "pgc-h-arrow-right" >1 Some diseases encountered by populus macrophylla and some corresponding control measures</h1>
1.1 Powdery mildew of boxwood macrophylla
The leaves of the large-leaved boxwood are the main harm of the disease, and when it occurs severely, it can also infect the new shoots. The pathogen overwinters in the form of a gray membranous bacterial layer in late autumn and winter, and in April of the following year, when the temperature is above 18 ° C and 70 to 85% is the relative humidity of the air, that is, when the new shoots of the large-leaf boxwood are in the 1-leaf stage, a large number of conidia will be produced by the pathogens on the old leaves, and by wind transmission to the new leaves, they will germinate on the new leaves, will produce bud tubes, and will invade the tissues in the later time.
Some corresponding prevention and control methods can be used: the first is to carry out appropriate pruning to enhance its permeability. The second is when you are just sick, 70% methyl tolbuzin 700 times liquid, 25% powder rust 1300 times liquid, 50% antibacterial special wettable powder 800 times liquid can be sprayed alternately.
1.2 Large-leaved boxwood brown spot disease
Wintering is carried out in the form of mycelium and sick lyses in the place of sick spots, in the second half of May every year, the temperature will change to about 25 ° C, the conidia will be produced by the old disease spots of the sick ovations, and begin to carry out the initial infection, in general, the lower part of the old leaves are first affected, once the old leaves are affected, the brown-green spots will be born on the leaves, slowly turning yellow and becoming brown.
Some corresponding control methods can be used: The first is to choose robust seedlings that are not sick when planting. The second is that 50% of the antibacterial special wettable powder 800 to 1000 times liquid, 75% bacillus 500 times liquid or 50% carbendazim 500 times liquid can be sprayed in early June to July to prevent and reduce the incidence, spray once every 10 to 15 days, the number of continuous sprays is three times. The third is to remove the fallen leaves in the winter and burn them together.
<h1 class = "pgc-h-arrow-right" >2 Some pests encountered by populus macrophylla and some corresponding control measures</h1>
2.1 Large-leaved boxwood silk leaf borer
Some of the characteristics of this insect's harm: the larvae can be connected with the leaves and young branches around the silk as a temporary nest, and then feed in it, and the final result is the death of the seedlings. In the northern regions it can produce two to three generations a year, it overwinters in the form of larvae in the buds to form a thin cocoon, adults are sleeping during the day and come out at night, is light-oriented.
Some corresponding control methods can be used: the first is artificial hunting, when the adults are in the egg laying stage, combined with the pruning of seedlings, the egg blocks and insect buds are removed and burned together. The second is to use black light to use light to trap during the adult stage. Third, when the larval damage is severe, 4.5% high-efficiency cypermethrin 2000 times liquid or 50% borer pine emulsion 1000 times liquid or Bt emulsion 500 times liquid spray can be sprayed for control. Turn over the soil at the roots to kill the overwintering pupae.
2.2 Japanese Kamewasuke
Some of the characteristics of this insect to carry out the damage: a generation occurs in a year's time, the wintering is carried out in the form of fertilized female adults on the branches of the tree, the eggs begin to be laid in May of the following year, the peak of egg laying in the first and middle of June, the inside of the shell is the place where the eggs are laid, about 1000 is the average number of eggs that can be laid per female adult, about 20 days is its egg stage; the peak period of nymph incubation is in late June to mid-July, and the newly hatched nymphs will climb to the leaves and harm the leaves Then the fixed sting sucks in the juice, and then the waxy substance is secreted, and the star-like shell slowly forms.
Some corresponding control methods can be adopted: First, when purchasing seedlings in the field, the quarantine procedures of plants must be strictly implemented to prevent the artificial spread of pests. The second is the practice of rotational planting, the garden should be cleaned up in time, the weeds, fallen leaves, diseases and insect branches are burned together, and the number of pests that overwinter is reduced; fertilization should be carried out reasonably, and the resistance of the plants should be enhanced; when pruning should be reasonable, its ventilation and light transmission should be better, and the living environment of the mesomorphic species should be changed, so as to weaken its reproductive ability, thereby reducing its harm. The third 150-200 times neem oil emulsion or washing powder diesel emulsion or 1% matrine 1000-2000 times liquid or 2000-2500 times vigorous killing is sprayed during the nymph bloom period, sprayed every 10 days or so, and the number of continuous sprays is three times. The fourth is to protect its natural enemies such as parasitic wasps.