This is an indication of a fungal infection. Fungal infections are usually the result of warm temperatures, high humidity and low light levels. Treat the plants with a systemic fungicide such as Phyton 27.

The old leaves naturally turn yellow and fall off as new leaves are produced. If your new leaves start to turn yellow, the first thing to check is the amount of light your orchid is receiving (review the culture sheet for the genus/species of your orchid). If light is not a problem, then check to see if you orchid is being subjected to low temperatures. There are also orchids that will lose all of their leaves naturally like the Dendrobium nobile hybrids do and will appear to be a "dead stick. See similar questions...

Older leaves die - this is the orchids' trick to living indefinitely: they discard the oldest parts of the plant as they grow new shoots. See similar questions...

There are several ways to prevent darkening of fruit; use pure ascorbic acid or ascorbic acid mixtures. Citric acid or lemon juice may sometimes be used but are not as effective as ascorbic acid. Some fruits which are to be cooked before serving may also be steamed to prevent browning. See similar questions...

Nashville tap water contains approximately 1 ppm phosphate. Available iron will chemically combine with this phosphate forming a compound which is insoluble by the plants. An iron deficiency condition known as iron chlorosis may result in these plants. The plants turn yellow and the leaves and stems both become very brittle. Fertilizers containing iron supplements will correct this condition. See similar questions...

Yellow leaves can be a symptom of overwatering or a mineral deficiency. Clematis need regular watering but is it is important not to let them become waterlogged. Clematis are heavy feeders. The ACS endorses Gro-Power Fertilizer because it is an organic soil conditioner as well as a fertilizer and it contains the necessary minerals to keep clematis healthy. See similar questions...

Brown edges are often a sign of salt damage; the salt contents in our tap water can cause the damage and is often compound by insufficient water. Thoroughly water the plant (shrubs to 2 feet deep; trees to 3 feet deep to leach excess salts away from the roots. See similar questions...

Commonly called tipburn, this could be due to excess fertilization, especially with perto-chemical fertilizers. Chemical insect sprays from aerosol cans can cause tip burning. A cold area, such as near windows or doors can also cause brown edges. Stop feeding with petro-chemical fertilizers and chemical insect sprays. Water well for 1-4 weeks depending on the plant and then resume feeding with Eartheart 18-16-9 All Purpose Plant Food or Eartheart All Purpose Insect Spray. See similar questions...

By dipping apple slices in a 1-part lemon juice to 3-parts water mixture, you can slow down the browning process. See similar questions...

Over time, the high temperatures of sterilization will discolor the gel in a FermProbe. This is often referred to as carmelization. It is normal, and in no way affects the performance of the electrode. This color change can also be used to approximate the age of the electrode. See similar questions...

Azaleas are acid lovers. Certain minerals, including iron, are more available at lower pH values. Yellow leaves on azaleas can indicate an iron deficiency because (1) not enough iron is present in the soil for the azaleas to utilize, or, more commonly, (2) the pH is too high to release the iron that is present. Azalea fertilizer is usually a sufficient acidifier to keep the soil within the proper pH range for maximum nutrient availability. See similar questions...

Over watering is the culprit, so back off. It will not reverse the rot, but you can take off the leaves from the stem, allow it to cure for a day and repot in pasteurized well-drained soil. See similar questions...

It could be just the natural ageing of the leaves. It may mean a lack of water or check the leaves for blackspot. Even a rose that has been nearly defoliated by blackspot may be reinvigorated by summer pruning back to 18 inches or so. Remove and destroy all the affected leaves. Do not put them in the compost pile. See similar questions...

Driftwoods can come from many sources, and some contain more organic material than others. The ones which still have organic material will still do some minor decomposition in the tank, and will gradually "leak" out tannic acid, the compound that turns water a brownish tea color. This generally won't hurt fish, and some soft water fish actually prefer the tannins, because it softens the water and simulates the natural environment of the Amazon River. See similar questions...

The colour of chips when cooked has very little to do with how they are cooked, and is almost entirely due to the potatoes used. If the potatoes have too high a sugar content, they will produce dark brown chips instead of golden chips. The potatoes selected for Potato Lovers Potatoes for Chipping not only have the optimum sugar content for golden chips, they have been stored in such a way that ensures the sugar content remains at the correct level. See similar questions...

Use a can of SP-101 White FlameProof Paint sprayed inside the small end of the exhaust system prior to installing the headers. Spray one can down each header. Do not worry about how it looks; just try to get it to run down the tubes evenly. If it drips out the other side, that is good. Clean off any over spray immediately with a strong solvent. This will virtually stop ceramic headers from browning and the bluing on chrome will be reduced to a ½ inch or less. See similar questions...

This is normal throughout the year, however it is most noticeable during the Spring time. All leaves will be replaced over the course of one year, so naturally you will see a lot of yellow and brown foliage as the new leaves form. Temperate bamboo are evergreen and if all is well with the planting, it should never be completely barren. The tips of the leaves are often brown and this can be caused by many factors. In most cases it is wind damage, but it can also be caused from improper watering. See similar questions...

This usually indicates a watering problem, either too dry or too wet. Or it could be lack of nutrients. Letting a wave petunia wilt will cause the leaves to turn yellow. If it has been wilting for some time, it could cause the leaves to die. If this happens, the best things to do are prune back the plant and watch the soil to give it the correct amount of water. Feed it in a day or two. Many times the plant will re-grow and come out of it fine. See similar questions...

It is normal for some of the leaves on bamboo to turn yellow and drop. This occurs throughout the year, but it is particularly noticeable in the spring. The dropped leaves will be replaced with new leaves. Other causes of yellowing leaves are stress, drought, excess water and lack of nutrients. See similar questions...