What are the black bugs on clivia, and how do you prevent and control the pest?
Black bugs appearing on clivia is also a fairly common situation during the clivia growing process. Many friends feel at a loss about this, because they may not know what these bugs are, let alone how to deal with this kind of bug and how to prevent and control them.
It is said that the common pests in the clivia growing process are mainly three kinds: scale insects, snails and nematodes. Among them, nematodes are white, and snails are not black either, at least their shells are close to white. From this, it can be seen that the black bugs appearing on clivia are mostly scale insects.
In fact, scale insects, strictly speaking, are not black either, but brown.
The brown soft scale is a pest with piercing-sucking mouthparts. The female adult of this pest is oval or long oval, flat, slightly raised on the back, generally 3-4 cm long and 3-3.5 cm wide, with a round and narrow front end and an enlarged rear end, usually light yellowish brown, yellow or reddish brown, with the body surface soft or slightly hardened, forming an irregular grid-like pattern, 7-8 antennal segments, one pair of eyes, reddish brown, and legs thin or of medium thickness. Newly hatched nymphs are oval, slightly round on the upper part and pointed on the lower part, pale yellow, 0.6 mm long and 0.3 mm wide. Nymphs are long oval, flat, slightly raised on the back, light yellowish brown, with marginal hairs along the body edge, and a pair of very long caudal marginal hairs reaching half the body length, similar in appearance to the adult.
I. Occurrence pattern
The brown soft scale mostly occurs in hot and humid seasons, and is also likely to occur indoors in winter. The brown soft scale often gathers on clivia leaf sheaths, affecting clivia photosynthesis, making clivia grow poorly, causing leaves to wither and lose ornamental value. Scale insects themselves have strong reproductive capacity, and most of their bodies are covered with a waxy shell, giving them strong resistance to pesticides. If not controlled in time, in severe cases they can also cause the entire clivia plant to die.
II. Control techniques
1. Manual removal: Scale insects use their slender stylets to pierce deeply into the tissues of clivia and suck the plant's nutrients. Once they leave the plant body, they cannot survive. Therefore, manual removal can be used. Use tools such as bamboo sticks or small wooden sticks to gently wipe off the scale insects and soot-like matter, then scrub with clean water. During the removal process, do not cause wounds to the leaves, to prevent infection by other diseases. The best time for manual removal of scale insects is during the nymph and adult stages of the scale insects. When adults are laying eggs, the eggs should also be scraped off together.
2. Chemical control: Chemical pesticide control of scale insects is the main method for large-scale control of scale insects. Newly hatched nymphs have a relatively thin protective layer of gelatinous and waxy substances and are easy to absorb pesticides. You can seize this favorable opportunity and use contact insecticides to control scale insects. You can choose 80% dichlorvos emulsion at 1000-1500 times dilution, 50% fenitrothion at 1000 times dilution, 40% dimethoate at 1000-1500 times dilution, etc. for spraying to kill them. During operation, every part with pests must be sprayed. For scale insects older than the 2nd instar, because the body is covered with gelatinous and waxy substances, high-efficiency and low-toxicity insecticides must be selected for control, such as 40% dimethoate at 1000-1500 times dilution, 50% emulsifiable concentrate malathion at 800-1000 times dilution, or 50% emulsifiable concentrate ethion at 1000-1500 times dilution for spraying, all of which can achieve a control effect.
3. Biological control: Mainly use the natural enemies of scale insects - ladybugs, parasitic wasps, parasitic fungi, etc. Especially among ladybugs, the red-margined black ladybug can prey on 2000 scale insects in its lifetime. This insect has a death-feigning behavior and is easy to catch. After catching it, it can be put in a breathable paper bag for later use.
It is said that although manual removal of scale insects is simple, it only treats the symptoms and not the root cause, and the workload is quite large. Therefore, when scale insect pests occur, chemical control should be the most effective method.