Get out your paintbrushes because it’s May and now is the time to start hand pollinating atemoya trees.
We have about 60 trees on the farm but if you’ve got just one or two, you can enhance fruit-setting by learning how to pollinate them yourself.
The nitidulid beetle, which is the insect pollinator, can be found in Hawaii and other tropical and subtropical climates, however, you can increase your yield dramatically with a little effort on your part.
An atemoya is a hybrid and a cross between a sugar apple and a cherimoya. Hybrids are not true to seed. If you’ve planted this tree from seed, chances are you have something else. It’s a good idea to buy a grafted atemoya from a reputable nursery and in four to five years you can expect some fruit. The farm has an on going project to graft about 50 trees within the next year.
The tree has hermaphroditic flowers, which means that they are at first female and later turn into male. The females are usually closed and open slightly when they are receptive to pollen. The females are most fertile between the hours of 2:00 and 4:00 p.m. As the 5:00 p.m. hour approaches, some start to turn into a male flower and they will open fully like helicopter blades exposing the pollen.
You can collect the pollen by brushing it off into a little jar (find one with an air tight lid). You may have to work fast because honey bees will take all the pollen quickly. Many times I have fought off a bee on a male flower, especially when there seems to be a shortage of pollen that day.
Collect as much pollen as you can around 5:00 p.m. when the males start to open and start to look for female flowers. You can pollinate as you collect pollen or you can seal it in a lidded container in your refrigerator for use the next day. If you live in a humid environment, like we do, you may find female flowers that are receptive to pollen after 4:00 p.m. In fact, I do most of my pollinating at the same time I collect pollen. You can tell if a female flower is ready by the stigma being wet and receptive.
Look for female flowers that are mature looking as if they are ready to open or are slightly open. You can pry open the petals and insert pollen. Take a small paintbrush (like the ones used in painting water colors) and dip it into your pollen. Gently open the female petals and push in the loaded paintbrush and move it about to deposit the pollen on the stigma. You will soon be able to juggle paintbrush, pollen jar and flowers like a pro with your hands.
Because I have many trees, I usually only hand pollinate the flowers that I can reach. In addition, I often snap off one of the petals at the tip so that I know this flower has been pollinated. Often, I am surprised by the amount of fruit that is set in the higher branches, but you can definitely tell the greater yield is at arms length. I can easily spend an hour or longer at this activity not reaching all of the trees in my orchard. Luckily, I sometimes recruit help. You will find flowers on your trees for up to two or three months. For me, this translates into a lot of time pollinating.
The fruit is well worth the effort and by August until December the fruit will become mature. The fruit does not usually ripen on the tree so you must know when the time is right to pick it. Look for the larger fruits and the color will change from medium green to a lighter shade of green.
In addition, you will find white or yellow coloring between the bumps or areoles especially closer to the stem. Clip off the fruit at the stem with hand clippers and handle gently. If picked correctly, it should ripen in three to four days. It will give way to gentle pressure when lightly squeezed. The fruit itself is very juicy and sweet.
I have heard a few complaints about these fruits turning brown and dying before they are ripe. I think this is mostly due to oriental, or melon fruit flies and chalcid wasps. You can tell the chalcid wasp infestation by the small holes bored into the fruit at the internal location of the seed. I found that trees that are well covered by other trees in the orchard produce more fruit with less pests than the ones exposed on all sides. Remove and destroy infected fruits. Perhaps your best defense is to make sure your trees get adequate fertilizers and because this tree is deciduous (drops all its leaves once a year), make sure to include some nitrogen.
Start examining your tree now for flowers and take a few minutes a day to inspect, collect pollen and pollinate. It’s a very relaxing and peaceful actively. I also have grown quite fond of the nice smell of the flowers and the sound of the bees at work. It may well be my favorite part of the day.