OK, i have notice substantial fruit drop in my apricot tree called Sugar Pearls, this year i am going to do something about it, i did some research about why this happens and the common reason are not the reason i have except one low pollination, So my problem is the lack of pollination so the tree aborts unviable fruit at about pea size. my protocol is to spray the tree at:
1,5 gallons of water,
three drops of down dish soap,
one 325 mg aspirin.
600 mailgrams of vitamin B1
4 grams of NAA,
then spray the tree till all of the leaves are covered, the reason for this is to inhibit the signal of fruit drop, this process will be repeated on day 5 and on day 10 from peddle drop, and repeated again every two weeks till harvest.
NAA is one of the main tools used to thin fruit. I rely heavily on it each year for fruitlet thinning of apples.
With apples its 5-20mm for best results. and 3-4 ounces / 100gal.
I use a horticultural oil for adjuvant.
When using NAA the rule is that you dont want to use too much or you may end up with the opposite effect and stick the fruit instead of thinning them. Problem with using it to stick apples is that you end up with pigmy apples.
I have no idea about using it with apricots. Here, we dont get enough apricots to worry about thinning and I definitely dont have any experience with your recipe for sticking fruit.
I was reading research paper that the drop signals are inhibited by a hormone called auxin, NAA reinforces that auxin, B1 reduces stress on tree, the asprin also helps block the drop signals. If you look up research papers on the topic of preventing fruit drop they talk about the methods to keep your fruit on the tree. My apricot is loaded with tiny apricots by the hundreds, but in two weeks i will lose 70 to 90% at drop, Hormex is a product that has NAA and B1, they claim it will help with friut retention. I will be getting this product in a few days. I will keep you posted if this works. Right now i made my own to start the process. But will use Hormex once i get it.
I have had fruit nodes develop into apricots without viable seeds inside them, they survived the culling or abort process, so i reason that if the drop signal can be inhibited unviable fruit will develop into harvestable apricots.
From what I have read, plant auxins are complex such that they are either cause an intended or unintended effects depending on amounts used, environmental factors and growth phase. I think it’s common among all plants to drop fruits that the plant determines waste of its resources while bulking up other fruits on the same branch. I have seen some fruitlets doesn’t go beyond dime sized while others have grown to dollar sized.
Just plant more apricots varieties and wild craft them. Don’t be a slave to one tree. But maybe it is your hobby. Personally, I don’t like problem child trees, and it is not my hobby.
I had 5 or 6 varieties of apricots for about 12 years. I pulled out all my apricots. Very spotty production in Z6. Replaced them with peaches. If I had tons of land, I’d plant all sort of apricots and let them go. Every few years you get a gift in Z6.
i have 4 apricot trees, one is 17 years old, and this year the mason bees could not get out due to the rain and wind at bloom time, that tree is covered with pea sized fruit right now, i know in a week there will be 90% less than what is on the tree. So I’m going to see if i can change that outcome. Aspirin also boosts Auxin, NAA at higher does raises Auxin, so i have hopes.
I kept having fruit drop from Black Ice plum and it turned out to be blossom blight. I don’t know if that is true for you, but it could be something other than a hormone issue.
i’m looking to force the tree to keep it’s unviable fruit, that is why i’m doing what i am doing. the tree aborts’ the fruit without an embryo or seed development, some times fruit does survive the cull, and i have seen fruit without a seed inside the hard shell after cracking it open, so it’s possible to circumvent fruit drop because it does happen naturally without my help. Sea weed could help in this regard too, Sea weed has Auxins and Cytokinins that may stop fruit drop if dosages are right.
Updates, it appears i got a harvest of apricots this year using this protocol, i got ten fruits that were very good, i started the protocol late so i will assume i should start it earlier at bud swell in the spring, and repeat every ten days. typically i get two or none from year to year, I did have a Hunza apricot bloom nearby but it only had 15 to 20 flowers, and almost no mason bees paying attention to it, they all wanted the Sugar perils bloomage, So i suspect i forced the apricot to hang onto more fruit. i originally thought i had faild.
I was assuming this naa concoction was a one off that you were trying because it was already past bloom. If your thinking about next year why not just properly pollinate the tree during bloom and be guaranteed a crop?
I dont like to rely on the insects to pollinate some of my more special trees, especially the early bloomers like apricots so i will hand pollinate. This always gives me great results. My favorite and most lazy method is to clip a flowering branch from another variety and use it to brush over the flowers of the desired tree. Also, and much more meticulous, i can use a soft paint brush to transfer pollen.
In my case, for instance, where i have apriums located too far from any of my Japanese plum trees i will cut a few flower branches of Beauty and prop them into the aprium trees. This is assuming insect activity for pollination here.
i planted two more apricots a few years ago, they are still small trees, whereas the Sugar Perils is massive 16 feet tall and it’s as wide as it is tall, 8" trunk at the base and it’s 17 years old. i do have a photo of it here on the forum if you decide to look for it.