Archive for the ‘Beneficial Insects’ Category

Big-Eyed Bugs – Revised EDIS publication

The University of Florida recently revised and reissued publication#EENY252:  Big-Eyed Bugs, Geocoris spp. (Insecta: Hemiptera: Lygaeidae).  Big-eyed bugs are the beneficial predator that is often confused with harmful chinch bugs.  Big-eyed bugs, however are actually a beneficial predator that feeds on chinch bugs, aphids, and other pest insects.  Please read the linked publication, above, for more information, including detailed photos and a key that may be useful in identifying big-eyed bugs and chinch bugs.

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A Beneficial Insect to Papaya

Have you seen this cottony-looking mass on papaya trees in the landscape?  This mass is composed of the cocoons of braconid wasp larvae that emerged from one of the large sphinx moth caterpillars (hornworms) that feed on papaya.  Hornworms can be very damaging to papaya, so it’s a great sign when we see signs of this wasp.  Most likely, the hormworm that was attacked in this case is the juvenile ello sphinx moth, Erinnyis ello.

Papaya Beneficial insect: Brachonid wasp cocoons. You can see the hormworn's previous location in the center of the cottony mass. Look closely for emerging adult wasps. *click for detail* UF Laura Sanagorski

A few weeks ago I wrote about another beneficial Braconid wasp that attacks the tomato hornworm.  The lifecycle and mechanism of control for this one is similar.  The wasp lays its eggs just under the skin of the hormworm. When larvae emerge from the eggs, they begin feeding on the insides of the still-living hormworm. When the juvenile wasps have matured, they eat through the skin of the hornworm, and spin their cocoons, after which the hornworm will die.  Adult braconid wasps will then seek out other hormworms to attack.  The difference between this braconid wasp and some others is that the host hornworm is gone here, whereas in other cases we find it still intact.

The Braconid family is made up of over 1000 species of tiny wasps that pose no threat to humans.  Insects in this family act as parasitoids to control pest insects, including a number of harmful caterpillars, aphids, and other landscape pests.  These beneficial insects are another good reason to use pesticides responsibly in the landscape and to spot-treat when possible.

A Sign of Beneficials – Green Lacewing Eggs

Green Lacewing Eggs. UF Laura Sanagorski

Green Lacewings (Chrysopidae spp.) are some of our favorite beneficial insects in the landscape.  Have you ever seen a line of these little orbs on stalks on a customer’s property?

These are sometimes mistaken for a type of spore, but they are actually the eggs of Lacewings.  The eggs are laid on stalks because juveniles have such voracious appetites that they would eat their siblings if they weren’t separated.   Lacewings are  desirable predatory insects, as both young and adults feed on some of our worst landscape pests, including aphids and mealybugs.   They are known for eating substantial amounts of pests (for their small size) and for living a relatively long time for an insect (several months).   There are a number of different beneficial brown and green Lacewings; only the Green Lacewings lay stalked eggs.

Green Lacewing Adult Photo Credit: Frank Peairs, Colorado State University Bugwood.org

Lacewing Eggs as Shipped, in Corn Cob: Tiny green flecks are eggs *Click for Detail* UF Laura Sanagorski

You can purchase the eggs commercially from a number of sources.  Lacewing eggs are often shipped in shredded corn cob so the juveniles will have something to eat when they begin to hatch.  Otherwise, they may eat each other before they have been released in the landscape.  Lacewings are yet another reason to apply pesticides responsibly.  If you see signs of the Lacewing or its eggs on properties you manage, take care not to disturb them, and keep preserving their habitat.

Beneficial Insect to Veggie Pests – Cotesia congregatus

Cotesia congregatus Parasitoid Cocoons on Hornworm *Click for detail* > UF Laura Sanagorski<

I like to stress how nature tends to find a balance without our help, such as in the case of pest and beneficial insects.  The photo on the left is an example of the beneficial Cotesia congregatus wasp’s activity on tomato hornworm.  If you or your customers grow tomatoes, eggplant, peppers, etc.,  you know this hornworm can be really destructive.

The Cotesia congregatus wasp helps to keep hornworm populations in check.  This insect is part of the Braconid family, which is made up of over 1000 species of tiny wasps that pose no threat to humans.  Insects in this family act as parasitoids, which are organisms that spend most of their life attached in some way to their hosts, which will eventually die.  Wasps in this family are excellent biological control options for a number of harmful caterpillars, aphids, and other landscape pests.

Cotesia congregatus Parasitoid Cocoons on Hornworm *Click for detail* > UF Laura Sanagorski<

The lifecycle of the Cotesia congregatus is pretty interesting.  The wasp lays its eggs just under the skin of the hormworm.  When larvae emerge, they begin feeding on the insides of the hormworm, essentially eating it alive.  When the juvenile wasps have matured, they eat through the skin of the hornworm, and spin their cocoons.  In the picture above, you can see that most of the adults have emerged through the tops of the cocoons.  Although the hornworm won’t do much damage to plants throughout the  whole process, it will finally die after the adult wasps emerge.  The wasps will then mate and seek out other hormworms to attack.

Only 0.6% of all insects in the United States are considered pests.  Most insects are beneficial, or at least harmless to us, such as in the case of this braconid wasp.  This is good reason to apply pesticides responsibly.  If you see signs of this wasp on properties you manage, take care not to disturb them.