I am currently planting some chilli peppers and I noticed that around 4 of my plants are demonstrating similar symptoms. It is appears to be mildly contagious as the problem has spread from 1 plant to a nearby 2 other plants. I am not sure if it is caused by pest or caused by a viral disease.
Picture 1 is in an aerated kratky setup that's sharing a reservoir with 3 other plants. The 3 other plant does not have the same symptom. I think it's unlikely to be a nutritional deficiency.
Picture 2 is in a polybag that's sharing its space with 3 other plants. In that bag, 2 of the plant are demonstrating similar symptoms whereas the other 2 plant looks very healthy.
Picture 3 is also in a polybag that's sharing its space with 1 other plant. The other plant is very healthy and roughly twice the height of the diseased plant despite being fed the same thing and planted within the same time.
Thus to reiterate my question: Am I looking at a pest-infection or a viral-infection? If it's viral, how should I respond to the problem? Should I destroy the whole bag or the infected plant or pull out the healthy plant and replant it elsewhere or what?
Here's a few links to more images of the diseased plant (grainy pic, sorry):
It is probably spider or cyclamin mites. They show up this time of the year. I have it on my peppers too. It is hard to control.
1. If the plants are really badly infested and you have other plants around, cut your losses and get rid of them. It is hard for them to come back.
2. If the plants are in pots, isolate the good one from the bad ones to prevent spread
3. Lop off the tops of the peppers, bag and trash/burn the debris. Pick up all the leaves and peppers on the ground too.
4. Control methods
a. If they are in pots. Mix up a 5 gallon bucket of insecticidal soap and sulfur
I cover the pots with a plastic bag to keep the soil from dropping out. Put a couple of wood slats across the bucket and put the pepper head first into the bucket and let it sit there for a couple of minutes. Repeat with the other plants.
b. If the plants are in the ground
1. Lop of the tops and discard all the infested leaves you see. If the plant is still healthy you can take off a ll the leaves
and just leave the stems
2. Mites are ubiquitous so you also need to treat other infested plants you have as well.
3. Put a jet spray on your hose and literally blasts the leaves with water paying attention especially to the undersides of
the youngest leaves. You may have to do this daily.
4. Garlic Spray Insecticide
For aphids, whiteflies, and spider mites
1 whole garlic bulb
2 cups of water
1 gallon of water
Combine in blender the entire garlic bulb and two cups water, and blend on high speed until garlic is finely pureed. Put in storage container and set aside for a day. Strain out pulp, and then mix liquid with one gallon water in sprayer. Spray tops and bottoms of leaves thoroughly. Apply about once a week, and after a rain.
5. Sulfur spray.
You can get commercial fungicides containing copper sulfate and sulfur does kill mites, you need to get thorough
coverage under the leaves. Do not use on days exceeding 90 degrees or within one month before or after using an oil
spray.
3 in 1 spray works but contains pyrethrins that are toxic to beneficial insects. It may temporarily control the mites
but in the long run, use it only as a last resort to preserve the beneficial insects or you will be getting on the pesticide
treadmill.
You can mix your own spray. This is a general purpose spray, but you still have to do a test spray since some plants
may be sensitive.
1 gallon of water
2 heads of garlic processed in a food processor to a pulp
2 tsp cayenne powder
Add all ingredients to a pot and bring it to a boil for 5 minutes. Turn heat off and cool.
Refrigerate overnight and strain through cheesecloth.
Make sure you use gloves, protective clothing and eyewear when handling any chemicals.
In a one quart spray bottle
combine 1/2 cup rubbing alcohol
1 tsp insecticidal soap or diswashing soap like Dawn (unscented), ivory, or chrystal white (unscented)
2 1/2 tsp wettable sulfur.
Add garlic mixture to fill bottle and shake well.
Do not use on cucurbits. Do not use if temperatures are likely to exceed 90 degrees and do not use within one
before or after using an oil. Always test a new batch on one leaf only and wait 24 hours to make sure it is safe.
More is not better.
Thorough coverage is necessary especially on the undersides of the leaves. Spray in the early morning when it is
cool.
Spider mites? I don't think so though, because I'm living in Malaysia where it's hot and humid so it's not really conducive for their growth (and I've not seen any spider webs yet).
Spider and other pest mites are microscopic and very hard to see, though there are often a sort of "Fuzziness" under the leaves especially along the central leaf vein and where the veins branch. It's only when there is severe infestation that you may see actual webbing in leaf nodes, etc. but not always -- depends on species of mites.
Sometimes you need to magnify by as much as 50-100x to see them, though I suppose it depends on your eye sight acuity. I've had some success by combining my cellphone camera at maximum magnification with my kids' 10-15x magnifier. But I do being out the 60-300x digital microscope if I want to be absolutely sure.
One simple and effective way to test is to hold a piece of white paper under the leaf and flick the leaf from the top with your finger. If you see some tiny dust like specks on the paper -- red, brown, green, black... Try smearing them with your finger -- put the paper on a smooth surface press down and swipe. If the specks leave streaks, you definitely have mites.
