Durian fruit producers in Australia, Malaysia, Thailand, and other durian producing countries are waging a seemingly never ending war against three specific types of insects that are determined to ruin the producer’s annual harvest.
Both the coffee mealybug (Planococcus lilacinus) and the Pacific mealybug (Planococcus minor) have given more than a few Malaysian durian fruit producers headaches. Though the insects aren’t very big, when a swarm settles in a cultivated durian orchard, they do quite a bit of damage.
Both species of mealybugs are quite prolific. Females lay anywhere from 600-800 eggs at a time, which hatch in less than two weeks. Since the larva mature quickly, three generations can feast at the durian orchard in a single year.
When mealybugs land on a tree, they migrate towards the flower branches and fruit, where they proceed to suck at the developing fruit, draining it of its juice, giving the fruit an anemic looking appearance. As a result of the constant feeding by the mealyworms, it takes longer for the fruit to mature, and by the time it is ripe, it will be a great deal smaller than expected. When the producer is finally able to harvest the durian fruit, the fruits imperfect appearances will cause shoppers to pass it by.
One of the biggest problems the mealybugs create for durian fruit producers is that as they feed, they create a rich sugar by-product, called honeydew, which ants crave. Not only does the honeydew attract ants that can do a great deal of damage to the root, trunk, and bark of the durian trees, some species of ants have been known to become protective of the mealybugs and will drive away would be predators.
While female mealyworms are wingless, the males do have wings, making it easy for them to fly from one durian orchard to the next.
In addition to being attractive to ants, the presence of the honeydew on the durian tree’s delicate branches and leaves creates the perfect environment for sooty mold to grow.
Durian Seed Borer
Durian seed borers are a serious problem for durian fruit producers. They first arrive at the orchard as adult moths. One of the first things the lady durian seed borer does is lay between 100 and 200 eggs. This is when the trouble begins.
When they hatch, the larva is quite hungry, so they follow their instincts and seek the nearest food source. Which in this case is a still developing piece of durian fruit. The tiny larva burrows into the fruit and starts feasting. They stay tucked deep within the fruit until the larva makes it all the way through the pupal stage, at which point they exist the fruit as a fully developed moth who is ready to find a mate and lay more eggs.
While inside the fruit, the Durian seed borers larvae gorge themselves on the seed. This doesn’t sound like a bad thing until you realize that they’re contaminating the fruit’s meat with their feces. Something no one likes to eat. The only way to determine if a durian fruit borer has made its home inside of piece of fruit is by looking for a small hole in the exterior of the fruit. Of course, when you open the fruit, you’ll also see evidence of pest.
It takes about 10 days for the eggs to hatch after which it’s estimated it takes another 48 days for the durian borer larva to make it through the pupal stage and turn into a moth. The hole the durian fruit borer drills into the fruit is approximately 5.0-8.0 mm. in diameter. Once the durian fruit borer reaches adulthood, it lives 7-10 days.
Yellow Peach Moth
If you are touring a durian fruit orchard and spot a yellow peach moth, you’ll probably be enchanted by its cuteness and impressed by its beauty, but the owner of the durian fruit orchard will have a much different reaction. They’ll be infuriated by the presence
of this attractive moth. They know that it means big problems for their orchard
Much like the durian fruit borer, the yellow peach moth arrives at the durian orchard while their adults. At this point they find a nice tree and lay their eggs. The larvae is about 20mm long and very thin, making it nearly impossible to see as it seeks out the nearest developing durian fruit and starts gnawing its way through the fruit’s hull. It spends 2 or 3 weeks inside the fruit, filling it frass, which is later uses to make a cocoon for itself while it pupates. Because of the short lifespan of the yellow peach moth, it only takes one or two seasons for the entire orchard to be infested with yellow peach moths.