Q: The leaves on my plant are curling at the edges, and the new growth is yellow-brown and shriveled. I suspect a deficiency. What is causing this?
Deficiencies can be hard to pin down, but unfortunately these symptoms (especially if you started with high quailty soil and have been on a good feeding program) also may indicate the presence of broad or russet mites, or thrips. I can't tell you how many customers came into the store last June and July, heading straight for the calcium and magnesium boosters. It got to be habit to caution them to check also for the presence of these pests. Often the infestation starts low in the branches and works up the plant. The leaf curling, or "canoeing" of the leaves is the initial symptom, then apparently some of these pests actually carry the hatching offspring to where the new growth is coming out so that they can feed on the tender growth.
If you are seeing these signs, take your handheld microscope (you do have one, right?) and examine the underside of the leaves. Thrips larvae look like squirming maggots, and broad mites look like tiny spider mites. You may be able to see spider mites with your bare eye, but the broad and russet require a microscope. The adult mites may be hard to spot, but if you do have an infestation, you will be able to see the eggs, tiny spherical globes on the underside of the leave. Once you have identified your pest, treatment can be administered.
For thrips, our customers have had the best results using spinosad based sprays like Monterey Insect Spray. There are many other brands, just make sure the label says "spinosad." Follow the instructions on the label, and don't be afraid to follow up with more sprays after a few days.
For the broad mites, sulphur based sprays seemed to work best for our customers. Safer 3-in-1 is sulphur based. Some customers used their own sulphur concotions. There are sulpher sprays used for the grape industry as well. I've heard some growers also "burn" sulpher, but this may be frowned on by your local air pollution control agency.
Following both treatments, add an azadachtrin product like AzaMax to your watering regimen. The azadachtrin becomes systemic in the plant, and when the bugs take a bite, it really makes 'em sick.
To PREVENT these bugs from getting a foothold in your garden, you can use these precautionary steps:
1. Use a sulphur treatment in your nursery.
2. Use an azadachtrin product in your nursery and on your mother plants.
3. Start with seeds.
4. If you use cloned cuttings, dip them when you take them in a miticide. Keep your nursery stock away from your mother stock.
5. Avoid unproven nursery sources and get an assurance from your provider that your plants are mite free. Then dip them as soon as you get home anyway.
6. Check the plants frequently with your microscope. You'll often spot bugs before damage is widespread on your plants. If you see eggs or mites, treat for them as above.
|The miracle of the neem tree
Most garden enthusiasts are familiar with neem oil. Commonly used as a pest control, neem oil is the product of a tree most often found in tropical zones, particularly in India and pakistan.
Extremely drought resistant, the neem tree's products have many uses. Leaves are used like mothballs to protect stored cloth and linen. The seeds and fruits are crushed and pressed for the oil, which works as a non pesticidal insect inhibitor.
Non-toxic, their is some compound in the neem oil that acts as an anti-feedant and inhibitor to breeding. Oddly enough, while the compound has been identified as azadactrin, the affect it has on the insects isn't clear to scientists. Some describe the affect as something neurological that confuses the insect, causing it not to feed and breed.
While that alone makes the neem tree an admirable, there is much more to this renewable resource. In areas of desert, environment specialists are conducting experiments in using neem forests to reclaim the arid, unproductive land. Since neem trees can live in areas of light rainfall, they are perfect for anti-desertification. In areas where there is a water table but little rain, the neem tree can thrive. Once established, the tree provides shade and food for animals, reduces evaporation, and provides organic litter to start other types of vegetation. The roots tap deep, and help aerate and condition the soil.
Various parts of the neem tree are used for food, in comsmetics, to heal skin diseases, medicines, and even as a soil amendment. Containing nitrogen and potash, neem "meal" or cake is the byproduct of processing neem seeds and fruit in extracting the neem oil. Returned to the soil, neam meal provides those macronutrients, plus carbon, sulphur, calcium and magnesium as well as residual azadachtrin. Added as an amendment, growers believe their plants are much more resistant to insect infestation, particularly that of the various mites.
"Since I started using neem meal as an amendment, I have had no bug problems," said one of our sales reps who calls on the store. In these recent seasons of epedemic broad and russet mite infestaions, that could be great news particularly for organic growers who don't like to use the commonly adopted miticides like FloraMite, Avid and Forbid. As an amendment, neem meal is also much cheaper than most mite spray treatments. And if you can't find neem meal, you can use azadachtrin products like Azamax; feed it into the soil so the plant can uptake the azadachtrin. Growers in our circle who use this as a preventative were among those who did not experience any broad or russet mite infestations.
BTW, neem seed meal is not that easy to find, but yes, we do have it at the store, and are working on labels to sell bags smaller than 50 pounds. I expect neem meal to be a top option for those who like to amend their soils to feed their plants.