Yucca plant bug

Do you have yucca planted in your landscape?  Have you checked it lately for pest problems?  I know that it seems early to start checking for pests but I walked past the yucca at the office this week and it is covered with yucca plant bugs already.

Yucca plant bugs are in the order Hemiptera and are related to other sucking pests such as stink bugs and leaf-footed bugs, but are much smaller.  Adult yucca plant bugs have a bright reddish-orange head and thorax with dark bluish-black wings.  Immature yucca plant bugs (nymphs) look similar to adults but do not have fully developed wings.  Since immatures do not have their wings fully developed, they're more red than black in color.

Both immatures and adults feed on plants by piercing plant tissue with their mouthparts causing yellowing spots on the foliage.

These little critters can sometimes be a challenge to manage since when you go to treat for them, they all dive into the center of the yucca into the nooks and crannies to hide.  You can try products with active ingredients such as insecticidal soap, horticultural oil, azadirachtin (neem), pyrethrins or bifenthrin, cyfluthrin, or carbaryl.  You will need to get good coverage to make sure that you get the pesticide to where the insects are hiding (and be careful not to get stabbed by the yucca!).

Lygus bugs

I've been getting email and calls about small "stink bugs" on cruciferous crops lately.  I went out to our demonstration garden to see if I could rustle some up on what we have planted out there and I hit the jackpot.  I found Lygus bugs on the cabbage and some other plants (that I have no idea what they are...I went back out to look- they're fava beans).

Lygus bugs have a wide host range and have been found on over 350 plants.  These bugs will commonly begin the year in weedy areas and then move into adjacent areas (leading them into gardens and landscapes) when the weeds begin to decline.

Adults are about 1/4 of an inch long and come in a variety of colors (the ones I've been seeing are brownish-black with red dots on the tip of the hemelytra).  They have whitish markings behind the head and on the wings.  The back half of the front wing is held downward at an angle (so it appears that the bug backed into a wall).  Nymphs look similar to the adults, but are usually a yellow-green in color and lack fully developed wings.

Weed management is very important to help keep populations of tarnished plant bug in check.  Manage weeds to keep the bugs from colonizing areas adjacent to gardens and landscape areas. You can try vacuuming them up with a hand-held vacuum. Pesticides can be used to knock down heavy populations.  Look for active ingredients such as insecticidal soap, azadirachtin, pyrethrins, or pyrethroids.

Insects on Mountain Laurel

The mountain laurels are in bloom in Central Texas.  This is the time of year I walk around and any time I see a mountain laurel I take in a long, deep breath.  I LOVE the smell when mountain laurels are blooming.  It puts me in mind of grape bubble gum.

So while I enjoy the scent and beauty of the mountain laurel flowers, some people may be more concerned with insects they are finding on their mountain laurels.  The two common insects that I get questions about are the Red Mountain Laurel Mirid (mirids are plant bugs) and the Genista caterpillar.

Red mountain laurel mirids, Lopidea major, are quite stunning.  They are smallish, flattened, oval-shaped bugs that are a striking red and black.   These insects have piercing-sucking mouthparts that they use to feed on plant juices.  While the feeding can cause damage to the leaves- often disfiguring new growth- they do not seem to harm the tree overall.

Genista caterpillars are yellow-green with black and white spots.  They can grow to about 1 inch in length and will spin webbing on the mountain laurel.  The larval (caterpillar) stage has chewing mouthparts and is damaging by feeding on foliage.

For management, treat as needed.  You can try a contact insecticide on the mirids while a Bt kurstaki or spinosad product should work for the caterpillars.

Four-lined plant bug

Have you seen me?  Not me, as in me, Wizzie, but me as in me, this bug.  We have them in the demonstration garden and I've been getting reports of them from all over town.  Some people have seen damage, which is often mistaken for fungal damage. I suggest that you head out to the yard and start looking.

Four-lined plant bug with damage.

Four-lined plant bugs are brightly colored.  Nymphs (immatures) are red while older nymphs start to have wing pads with yellow and black stripes.  Adults have fully developed wings that are yellow and black striped.  Adults look similar to- and may be mistaken for- striped cucumber beetles.

These insects have piercing-sucking mouthparts they use to suck out plant juices.  The plant bugs suck out chlorophyll and leave a "window" between the upper and lower epidermis of the leaf. Damage appears as white, dark or translucent spots of foliage.  Feeding may also cause curling and browning.  Fortunately, damage is mostly cosmetic, but if you are trying to eat the foliage of the damaged plant it may become a problem.

The insects feed on a wide variety of hosts, including fruits and vegetables, annuals and perennials and  woody plants.  When disturbed, the insects are fairly good at hiding.  They either crawl to the underside of the leaves or drop to the ground to hide among foliage.

If you feel the need to manage these guys and gals, try insecticidal soap.  If that doesn't work, you can try azadirachtin (neem- concentrate, not oil; it's getting too hot to use oil formulations) or pyrethrins.  If that doesn't work then try a residual contact product.