Boxwood is a shrub that is eagerly planted in gardens and in containers on balconies and terraces. It tolerates pruning and can be formed into a variety of shapes, perfect for low fringed hedges. Sometimes, however, problems can be caused byboxwood diseasesand feeding on the plantboxwood pestsSee how to recognize them and learn about the best methods of combating diseases and pests of boxwood!
Diseases and pests of boxwood. Folded boxwood leaves, looking like
cabbage heads, indicate that the plant has been attacked by a pest - boxwood honey.
Boxwood diseases
Physiological dieback of boxwood leaves and shoots- in early spring, the youngest boxwood leaves, starting from the tips, turn rusty brown. These discolorations gradually expand to cover the entire surface of the leaf blade, and then also the shoots. This is due to the low temperature at the end of winter and the beginning of spring, as well as the winds drying plant tissues. The rapid increase in air temperature during this period favors the rapid beginning of vegetation of the above-ground parts of the plant, although the ground is still frozen, in such conditions the bushes, unable to replenish the lost water, react with the dieback of leaves and shoots, and as a result, the weakened organs may die over time as a result of fungus infestation .
To prevent this from happening, for the cultivation of boxwood you should choose positions sheltered from the drying spring winds, shade the plants with non-woven fabric in the period of danger and ensure adequate soil moisture.
Dieback of boxwood shoots- it is a boxwood disease with a similar name to that described above, but it is not physiological but is caused by an attack of pathogens. In spring, when the growth begins, the leaves of the youngest boxwood shoots turn light green and then yellow-brown. Brown, rapidly enlarging spots appear on the shoots, sometimes around the entire circumference of the shoot, some of which dies above the infection site. Necrosis may also extend to the base of the shoot, orange or black clusters of fungal spores can be seen on the surface of the dead tissues. Such symptoms indicate infestation by Volutella buxi and Macrophoma candollei. They are transferred to neighboring plants by water droplets or insects. Plants damaged by low temperature, dried out plants or planted on a substrate that are too wet for them are particularly easily infected. as well as frost or root damage caused by insects.Infected shoots should be cut below the dead tissue, above a strong side branching, then the plants should be sprayed 1-2 times with Topsin M 500 SC or Score 250 EC. You can also use biopreparations: Biochikol, Bioczos BR, Biosept Active.
Diseases and pests of boxwood. The Volutella buxi fungus causes boxwood shoot dieback.
Boxwood leaf spot- single white or light brown circular spots appear on the edge of the leaf blades, sometimes they blend together and cover the entire leaf surface, on the upper side of the leaf blade black clusters of fungal spores are visible, leaves and shoots may die over time. The cause of thisboxwood diseaseis infection by various species of Macrophoma candollei, Mycosphaerella patouillardi and Volutella buxi. The source of infection are spores which, together with water drops or by insects, are transferred to neighboring plants.He althy shrubs, which are in good condition, are very rarely infected, while the infection is favored by damage to the shrubs caused by low early spring temperatures. In case of signs of infection, cut out heavily infested shoots and burn, and spray the whole plants 1 to 2 times every 10 days, alternating Biosept 33 SL and Topsin M 500 SC.
Boxwood phytophthora- the first symptoms of thisboxwood diseasecan be seen on the leaves and young shoots. Leaves and the youngest shoots rapidly wilt, turn yellow, turn brown and die. After removing the plants from the ground, you can see a very underdeveloped, rotting root system. Necrosis appears at the root base, which over time also spreads to the base of the shoot. The observation of such a change at the base of the shoot allows us to say with 100% certainty that it is phytophthorosis.
The cause of this boxwood disease isinfection by Phytophthora cinnamomi or Phytophthora nicotianae, infection particularly quickly can grow on plantations in nurseries.To prevent this disease, do not plant boxwood in substrates with a high content of organic matter - especially in peat - where the fungus develops very intensively, do not grow boxwood in the substrate after plants on which the fungus may have occurred, for example: yews, cypresses, fir trees , rhododendrons or pine trees, and keep the substrate in the containers too moist. Remove diseased plants from plantings and water the rest with fungicides, e.g. Aliette 80 WG, Magnicur Energy 840 SL or Biosept Active.
Boxwood pests
Boxwood honey - this is the most commonboxwood pestBoxwood leaves curl and look like cabbage heads, the pest releases honey dew and wax in the form of snow-white twisted threads during feeding. This damage is caused by the larvae and adults of the boxwood (Spanioneura buxi), sucking the juices from the leaves of the boxwood.It is the most common pest that attacks boxwood shrubs. Systematic shrub cutting helps preventively, we start spraying in May, when we notice the first symptoms of honey feeding. Spray the plants with Polysect Boxwood 005 SL Ultra, Mospilan 20 SP or Provado Plus AE (ready-to-use spray preparation). You can also use Emulpar 940 EC, which is based on natural ingredients and is environmentally safe.
Diseases and pests of boxwood. Small yellow spots and browning of the leaves
causes the spider mite boxwood.
Boxwood spider mite- pests feed on the underside of the leaves, and the effects of their existence can be seen on the upper side of the leaf blade. They are tiny yellow spots which blend into spots over time. Boxwood leaves turn brown and wilt. After noticing damage to the leaves, the plants should be sprayed with a spider mite preparation, e.g.Karate Zeon 050 CS. In early spring, before the vegetation starts, the wintering eggs of spider mites should be destroyed by spraying paraffin oil with the ecological preparation Promanal 60 EC (the preparation contains pure paraffin oil). Thanks to this, there is a chance to avoid the need for chemical protection during the growing season.
Boxwood moth- a pest that appeared in Poland only a few years ago, but quickly began to cause great damage. It attacks various species of boxwood. An adult insect is a butterfly with white wings with a dark edging. However, the most harmful for boxwood are its larvae - green caterpillars up to 4 cm long. Their body is green with longitudinal black stripes. First,gnaw the edges of the boxwood leaves inside the crown of , making them difficult to spot at first. Then they bite the whole leaves or skeletonize them strongly, stripping all the boxwood shoots, including the outer ones.
Boxwood bushes in search of caterpillars need to be searched from Apriluntil September.As soon as you notice the larvae of the boxwood moth, you have to collect them by hand or shake them on a foil placed under the shrub, and then destroy (crush, crush or burn). With more bushes, when we are not able to catch all the caterpillars, you need to use insecticides.
The safe-to-use biological Lepinox Plus preparation will be the best choice. It contains the bacterium Bacillus thuringiensis, which infects the caterpillars of the box tree moth, causing them to die. It is a selective preparation, safe for beneficial insects, it only destroys the caterpillars of the pest. One 10g sachet of this preparation should be dissolved in 5 liters of water and sprayed. Pay attention to the spraying also reaching the inside of the boxwood crown.
As an aid in combating the box tree moth, we can also use agents with a systemic effect , which fight other sucking and gnawing pests on boxwood leaves, but will also be helpful in the fight against the caterpillars of the box tree moth.These are Polysect Boxwood 005 SL Ultra and Mospilan 20 SP.
Systemic action means that the preparation is quickly absorbed by the green parts of the plant and is transported along with the juices throughout the plant.Insects and caterpillars that eat sap die even if they are not sprayed directly .
Apple shellfish- this pest causes shoot dieback, diminishing leaves and limiting the growth of boxwood. Brown or gray insects' shields visible on the shoots. The pest can be recognized by the characteristic appearance of females, whose body is hidden under a brownish or gray comma-shaped shield about 2-3 mm long. Females lay eggs and place them under their body, then die. The eggs hibernate under the female shield so that the larvae hatch in May of the following year. If the box trees are attacked by the apple shell, the plants must be sprayed twice every 14 days in May with one of the following preparations: Mospilan 20 SP (0.02% concentration) or Provado Plus AE (spray preparation).
Boxwood wander- this is a spelter that causes deformation and fineness of leaf blades on young growths in the spring. At the beginning of summer, in order to develop a new generation, pests move to new leaf buds, causing them to enlarge and change their color from green to brown. Theseboxwood pestsare very small and cannot be seen with the naked eye, so we need to recognize them by visible damage to leaves and leaf buds. Spraying against boxwood smoker is done in spring with Karate Zeon 050 CS or another acaricide. Spraying must be repeated after about a week.
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