But true… like any planted exhibit or landscape our Rainforest exhibit has its share of unwanted pests. Horticulture biologists have become very creative in figuring out ways to prevent these pests (mostly insects) from damaging our plants without causing harm to the other animals living in our forest like the butterflies, Amazon fish and birds.
Lucky for us the Rainforest isn’t just a collection of pretty plants, it’s also a complex living system that we can use to our advantage. Of course the best pest prevention is to grow healthy plants. Every day we give lots of attention to all our plants, big and small, to keep them as healthy as possible and catch health problems early on.
Healthy plants are able to resist pests which reduces pest damage to the plants and slows down the growth of the pest population. When we see pests on the plants in our exhibit we first check to see what might be stressing the plant, making it susceptible to pests.
We also rely on the animals in the exhibit to help us out. We have naturally occurring spiders living in our forest that trap our pests and birds that will pick an insect snack off the plants now and then.
Of course we don’t want to use a lot of pesticide chemicals in the Rainforest that may harm our animals or our visitors so we rely on other strategies to control pests. What’s our favorite tool for pest control? WATER! Hosing pests off of plants is often as effective, if not more effective, than pesticides. Luckily we have volunteers to help us with the task.
In a real tropical rainforest, plants benefit from a diversity of naturally occurring predators and parasitoids that feed on insects in the forest and help keep them in check. We don’t have quite enough diversity of natural predators in our forest to manage our different pests so we have released our own beneficial insects to help keep pests under control.
Two of our most common pests, scale and mealybug are successfully controlled by our beneficial insects. Scale is a tiny (~1/4″) insect that pierces the plant with a straw like mouth parts. We have controlled scale using a tiny, non-stinging, parasitic wasp. We can tell that the highly magnified scale in the photo below was parasitized because of the perfectly round exit hole where the adult wasp emerged.
The mealybug in the photo below was parasitized too. The adult wasp popped the top off the mealybug when it emerged, like popping a lid off a can.
Mealybug, also feeds on plant sap through its straw-like mouth parts and is under attack from a few predators in our rainforest. The pink/orange pupa to the right in the photo below is the midge Aphidioletes aphidmyza, which was released to control aphids and decided to expand its diet.
And… we release the well named ‘Mealybug destroyer’ beetle Cryptolaemus montrouzieri which feeds voraciously on this pest.
All in all, our goal is to have an attractive exhibit with healthy plants and animals. We don’t mind having a few pests around as long as they don’t get in the way!