Thrips are not as easy to eradicate from your Violets or any other plant, as some people may contend. This is mostly due to there being 5 individual stages of the Thrips development, all the way from eggs to an adult Thrip. Each stage requires individualized and highly specific attention and treatment, due to Thrips developing on different areas of the plant and at different times. Thrip development is not only in the anthers, where you can see evidence of their presence by spilled pollen on the petals from burrowing, but also in the soil, leaves and root system. Should only one area on just one plant remain not be treated and remain infested, an extremely high probability exists for your other plants to have or soon have Thrips as well. Remember, Thrips move quickly like ants and the adults will fly. Most Thrips are unseen, and the adults are a mere 1mm in length.
There is NO quick fix to eradicate Thrips, as there is no "one time" magic chemical treatment, that would not be extremely harmful to humans and simply removing flowers and repeatedly treating your plants with Neem oil will NEVER get rid of your Thrips, ever. To eradicate, one must employ a fairly complex yet simple approach, utilizing specific chemicals to be applied at different times. Doing otherwise has you end up with hybrid Thrips that exhibit a much stronger chemical/pesticide resistance/tolerance. I give credit to Pavel Enikeev who explained this eradication procedure in detail.
The difficulty with a true Thrip eradication process lies in the fact that insecticides do not address eggs. Until they begin to develop, no treatment on earth will help. Remember, female Thrips, in the absence of flowers, lays eggs in many locations of the plant, not just one specific area and even when treating with multiple insecticides, only adult Thrips and freshly emerging larve will die. Western Flower Thrips are already resistant to many time proven chemicals. The good news is that chemically treating, over specific time intervals, results in gradually destroying a newly surviving generation.
It is not always possible to see Thrips. More times than not, a Thrip infestation must be determined by observing traces of their destructive activity. Thrips cause brown, dried, empty anthers; pistil bases thickened and cause flowers to fade much more quickly than normal. Some people erroneously think Thrips prefer blue flowers, but this is not the case. Dark colored petals show spilled pollen more readily. That's the reason for the confusion.
Suggested measures to best keep your Violet collection safe:
- Never bring cut flowers or potted designer plants, including azalea or mini roses into your growing area. This includes newly purchased Violets.
- It's understood how one would want to purchase/”save” violets from Lowes or Home Depot especially for only a few bucks, but for your own safety, please don’t take a chance doing it. Those Big Box stores have extremely high plant turnover, seem to care only about making a quick buck and have much less regard for plant quality or protecting your grow area. Why jeopardize your collection with a $3.00 plant?
- After purchasing Violets (from anywhere), it's wise to keep them isolated from your main growing area for at least four weeks, monitoring them daily inspecting for any hint that they may be infected. In addition, provide preventive treatment for "Everything", especially thrips. When we see pollen fallen on petals, it is typically an indication of Thrip presence. Then it’s too late and your entire growing area must be treated.
- Again, do not introduce freshly bought plants or even plants from your garden, into the room where your violet collection is located, no matter what. Any new purchase should undergo prophylactic (preventative) treatment by one of the below methods, after which they should immediately be transplanted into fresh soil.
- When growing/collecting African Violets, no longer allow cut flower bouquets anywhere in your home, not only in the growing area/room.
- Should you exhibit, sell or purchase flowers is fairs, shows or retail stores , it is prudent to isolate your new plants after each event before re-introducing them to your grow area. All flowers and their stalks should be removed outside your home. Place them with your collection ONLY after preventative treatment for parasites. Please remember that preventive treatment saves you not only time and money but also the possible loss of your entire violet collection. Don't let that nightmare happen to you.
To protect yourself, whenever applying pesticides, in either chemical or powder form, always wear protective gloves, eye-cover, a long sleeve shirt and an approved respirator mask. It's that serious.
General Principals are:
Initial step is to physically remove all flowers, to decrease the young and adult population of thrips. You need to be ready to treat your AV’s for at least 4 weeks. With higher temperatures, Thrips propagate quickly (3-4 days), with lower temperature it could takes weeks. So if you want to expedite all process, increase the temperature in the growing area. You cannot eliminate any eggs, but you must still treat the soil, leaf, all buds and most importantly all at the same time, to address adult and larva thrips. Should, after the first treatment, some Thrips survive having developed a good tolerance to the chemical you used, so the next time you need to treat your AV’s with a different active ingredient. Change as many times as you need to eradicate them. Brand name of product could be different, but you should make sure that the active ingredient is new. That's crucial, repeat crucial. Be careful not to overwater AV’s and use anti fungicide to prevent root rot. For Thrips identifying presence, you can place yellow sticky strips to see if some Thrips become trapped.
Also for identifying presence, you can leave a few dark flowers and inspect them with a loupe(small magnifying glass)daily. A hastings Triplet 10x can readily be purchased for this on eBay. If you see spilled pollen, you have to continue with the insecticide to destroy all adult individuals and larvae that emerges from eggs. If you have a small collection, to increase efficiency, place the treated plants in a greenhouse: there the drug is prolonged and the pest is deprived of a chance to move to neighboring plants, on which he could “catch his breath”, “drink”and stay alive.
If you have small collection. A solution of insecticide is prepared in a small basin using warm water. Wrap the pot and soil in a plastic bag, turn the plant upside down and dip the entire plant into the solution for 10 seconds. After removing the plant and returning it to its normal position, you remove the bag and allow the rest of the liquid to drain from the leaves into the ground (before this treatment, the soil must be slightly dry). Violets may be dried on a newspaper, folded in several layers. With this method, no untreated areas remain on the plant. Economically, quickly and reliably, it is practically safe for human respiratory organs, since the drug is not sprayed in the air. A huge plus is the simultaneous prevention (or treatment) of the tick and mealybug. Treatment is best done in a confined room with ventilation to the outside.
First stage: Water your plants 2 days prior to treating for Thrips, no sooner. You will be prepararing the insecticide and then spraying the plants with the different insecticide.
The second stage - After 3 days: spray and water your plants without spillage. After a day or two after that, you need carefully water the violets (without moistening the plants themselves, preferably from a pallet).
The third treatment (3-4 days after the second) - Spray the plants and shed the soil. The third treatment can be carried out with 1-2% solution of insecticide.
The last, fourth step, could be repeating the first step. This is an extremely effective eradication method; at the same time, you can eradicate the mealybugs, mites and scales, should they have been present.