When Orchids Need Help
Like all other plants, when orchids are grown in poor conditions, they become vulnerable to insect attacks or diseases. On the other hand, when you fulfill the basic requirements of orchids, these plants grow up to be exceptionally tough.
Moreover, they also remain free from troubles caused by insects and diseases. All said and done your best advantage while dealing with problems faced by plants is your ability to meticulously detect anything that might appear to be unusual.
In case you come across any problem with your orchid, first you need to check the growing conditions to ensure that your plant is receiving everything it requires to thrive well.
At the same time, you need to make sure that the leaves of the orchid are clean and also the growing region of the orchid is not only clean, but also does not have any debris. The usual signs of danger together with the apparent causes as well as remedies are described briefly below.
As it has been found that often the same growing conditions are responsible for the basic cause that troubles the orchids, it would be more prudent to stay away from them right from the beginning. These precursors of troubles are generally pests and diseases.
Fungi and bacteria
It is worth mentioning here that almost always water is a major factor in the development of diseases that trouble orchids. As we are aware that a number of fungi free spores into the atmosphere and these spores may drop on the vigorous plants and transmit a disease to them.
Fungus Botrytis releases spores that can germinate as well as infect the orchids when the relative humidity is about 100 percent, especially when there is water, for instant the slightest film of dew on the surface. This particular fungal infection is mainly to be blamed the flowers developing spots.
What is worse is that it takes only six hours for the spores to germinate and infect the plants when the conditions are favourable. On the other hand, some diseases that trouble orchids are spread by water contaminated at the source or from the splashing in the region of the infected surfaces.
These diseases include bacterial rots as well as the brown or soft black rots due to Pythium or Phytophthora. Hence, it is always advised that you should never allow stagnant water to be left on the crown or any other part of the orchid. There are so many chemicals available to check the diseases that trouble orchids that will leave one bewildered.
Nearly all these chemicals are for preventing the diseases from occurring. When you coat your orchid with such chemicals, the diseases would find the environment extremely toxic to establish them. In fact, a number of fungicides are systemic – they are not only capable of entering the plant, move around it and protect it from inside.
However, many fungicides that are available these days are successful against a few diseases, but not effective against others. What is worse is that these fungicides may also make the other diseases to aggravate. The main problem faced by an orchid grower is diagnosing the diseases and sometimes they need to employ hit-or-miss methods.
Below is a shortlist of the chemicals that are available for protecting your orchids from diseases and pests. The chemicals have been listed under their brand names.
This is a preventive fungicide that is successful in shielding the orchids from an array of fungal diseases. You may use Captan for drenching the potting media.
Mancozeb (Dithane, Manzate, Fore)
This also another preventive fungicide that protects your orchids from a number of diseases.
Rovral (Iprodione, Chipco)
This is a preventive systemic fungicide and is also capable of eradicating some infections that have already been established. This fungicide is extremely effectual against Botrytis. However, it is unfortunate that using it in excess may lead to development of restraint strains of the same diseases. Therefore, you should never apply this product in excess of thrice in a year.
Benlate is also a systemic fungicide. Use of this chemical helps to build up resistant strains very quickly, however, since it belongs to a different chemical group, this fungicide is an effective substitute of Rovral. It is important to mention here that you should never apply these products on a regular basis. But they are dependable and can be stored for emergencies. This fungicide is, however, not effectual against Pythium or Phytophthora.
Aliette (fosetyl aluminum)
This systemic fungicide is easily taken up by the leaves and roots of the orchids and provides the plants with long-term protection against both Pythium and Phytophthora.
Terrazole (Truban, Etridiazole)
This chemical is used to drench the soil or potting mix and works in the same manner as Aliette.
Quaternary ammonium compounds
These chemicals are marketed under various trade names and they are sold for a number of applications that range from getting rid of algae and moss to treatment of swimming pools. For plant protection, these compounds are sold under the trade names Physan, Consan and RD20 among several others.
Some people claim that these compounds are effectual against bacterial as well as fungal diseases. While using these compounds, you need to carefully as they need to be greatly diluted before use.
In fact, these are the sole products among all those mentioned above that will eliminate bacteria and even clear small patches of wet rot on the leaves when swabbed or you apply them to the areas affected by the disease after the removal of the rotten tissue. They are also effective for checking algae on the walls as well as roofs.
If you are unable to diagnose a bacterial or fungal disease affecting your orchid, it is advisable that you try everything possible until you find an effective solution. If you detect soft brown or black rots on the plant, you may try to swab or flood the affected area using Physan and subsequently drench the roots of the plant using either Aliette or Terrazole. If it is feasible, you should first cut out the rot.
If everything fails, you may try using Benlate or Rovral for treating some diseases having the above-mentioned symptoms. However, this should be the last resort. If you detect leaf spotting on your orchids, you may try using Benlate or Rovral once and subsequently spray the plants regularly with any effective fungicide that is protective, for instance Mancozeb or Captan.
Most of all, you should try to rectify the conditions that were responsible for allowing the disease to establish the disease. However, often this is easier said than done. While rotten roots often play hosts to diseases, if you allow the media to remain wet for a long period, it may possibly turn out to be the main reason for the diseases to establish themselves.
Often the media remains wet for long for two main reasons – either it has been watered in excess or very frequently. In addition, this also happens when the media breaks down. In such cases, you should take the orchid out of the pot and re-plant it in a fresh pot adding a new potting medium. Before this, don’t forget to get rid of the decayed/ rotten roots of the plant.
When viruses infect your orchid, it will display a number of symptoms on its foliage – for instance mottling, yellowish or dark streaks as well as blotches frequently with sunken surfaces of the leaves and sometimes in a mosaic or diamond pattern.
In addition, the flowers of the orchids may develop white or brown streaks. Sometimes the marking on the flowers may be of more intense colors. Diagnosing the precise disease affecting the plant may often be difficult because many of the above mentioned symptoms as apart from viruses may other things may be responsible for them.
You may suspect a virus attack in case the same markings appear on all the leaves and flowers of a particular orchid every year, while other similar plants are “clean”.
When this happens, unfortunately there is no cure available and you should destroy the infected plants or isolate them from the healthy plants so that they are also not infected. Insects often spread a virus from one plant to another, but the main threat is from the grower who handles the plant, particularly when he/she is cutting off the flowers or re-potting the plants.
Therefore, it is important to wash the hands before and after re-potting your prized plants. In addition, you need to sterilize the cutting tools by heating them until they become cherry red. Here is a word of caution – you should never use a used pot for planting another plant without sterilizing it.
Weeds are another problem for orchids. Therefore, it is important to keep the pots free of weeds. Often ferns may also come up in the pot and they may even look nice. However, they pose a challenge for the orchids and, hence, you should get rid of them. In fact, a form of Oxalis corniculata has turned out to be a pest of orchids worldwide.
This weed shoots off glossy black seeds to a significant distance and later the seedlings appear all around. When these seedlings are small you can easily pull them out, but as the plants become established beside a pseudo bulb, removing it may require taking the orchid out of the pot and even shaking off the entire potting medium.
This is a wearisome process. Instead, you may kill the weed by painting it with a solution containing weed killer. You may also apply glyphosate using a small artist’s brush. However, you need to be extremely careful to ensure that the weed killer does not come in contact with the orchid in any way. If it does, it will harm your valuable plant.