News-Star Sunday Article July 23rd 2017 Becky Emerson Carlberg It is too hot. The plants wilt every afternoon.   The steering wheel in my van could brand my fingers. The air conditioner is taking fewer rest breaks. Even the neighbors are quieter.   This time of year they either ride their lawnmowers to cut dead grass or [...]

News-Star Sunday Article July 23rd 2017

Aphids on the Tropical Milkweed

Becky Emerson Carlberg

It is too hot. The plants wilt every afternoon.   The steering wheel in my van could brand my fingers. The air conditioner is taking fewer rest breaks. Even the neighbors are quieter.   This time of year they either ride their lawnmowers to cut dead grass or ride their tractors to cut and bale hay.  The birds perch on the birdbaths panting. The cicadas and grasshoppers cry for rain from the trees.   Most outdoor activities are done early in the morning day or late in the afternoon. The deck is now very dry and what a fine time to paint the deck with the burnt ochre tinted waterproof sealant.   Nope, the temperature is too high. The job must wait until the temperature drops below 86 degrees and/or the afternoon sun is low on the horizon or after night settles and the stars have come out.   Can't depend on moonlight since it entered the new phase at 4:45 this morning. The 8'x12' treated wood deck is being waterproofed in stages.   Should be finished by September.

On the other hand the squirrels, spider mites, and aphids aren't the least bit phased. The squirrels shimmy up the pole at about ten in the morning and hang around the rest of the day digging into seeds. The spider mites just appeared recently.   They are into (actually on the underside of) heirloom tomato leaves, at least the Black Krim (Solanum lycopersicum 'Black Krim'.)   I feel rather responsible for the invasion.   Right next to the heirloom was the Mexican Marigold (Tagetes erecta.)   The Mexican native bloomed throughout the winter and spring, but not one single yellow flower can be found on the rather expansive greenery.   Nevertheless, the unobtrusive host plant provided a dandy home for one or possibly more of 1,200 species of the Acari (mite) family. The marigold was moved to the opposite side of the rain gauge.

Spider Mite damage on Black Krim tomato

Spider mites are not insects.   They are in the spider and scorpion family.   Right.eight legs, two body segments and the word spider give it away.   The female mite can lay 20 eggs a day for up to four weeks if hot dry conditions right now. You do the math. Spider mites love marigolds, blooming or not.  They launch themselves from the leaves, riding their little webs like flying carpets on air currents while searching for edible tasty plants.   They land, spin tiny webs on the undersides of leaves and proceed to eat. The Black Krim tomato, in my case, began to look sick and the fading green leaves were covered in thousands of itty bitty speckle freckles. I held a white sheet of paper below a leaf and tapped the leaf.   Tiny dots appeared and began frantically moving around on the paper.   Viola, the Krim has sucking visitors.

The Krim tomatoes are now ripening.   No way will I use any miticide or pesticide.   My hose nozzle has a jet setting.   As I blast the leaves I say goodbye to my little friends (?)   A week of pummeling the tomato with water will make it feel like it is going through a small car wash every day, but the spider mites will not appreciate the gesture of cleanliness.   The Black Krims are more delicate than other large tomatoes.   Their skin is thin and they are often ready to pick even though the top is still green with cracks.   The tomatoes are not firm but slightly soft and yield somewhat under pressure.   The flavor is magnificent, so the spider mite problem must be dealt with immediately.   There are more tomatoes coming on. My pieces of bacon, leaves of lettuce, slices of toast and jar of mayonnaise are waiting.

The aphid crews hit the tropical milkweeds (Asclepias curassivica) in large numbers, moving from plant to plant.   Oleander aphids (Aphis nerii) have been described as the granddaddy milkweed pest of them all.   Some call them little orange or yellow vampires. It is recommended to rub them off, hose them away, spray the offending insects with isopropyl alcohol followed by a water wash, throw coffee grounds around the base of the milkweed or plant different varieties of milkweed in the same area. Of course the people that gave these hints also said onions and marigolds repel aphids.   Now I am in a quandary.   Should I put the Mexican marigold by the tropical milkweeds?   The Black Krim said go for it, so my Mexican marigold was moved from the rain gauge to the milkweeds.   I then discovered the aphids had gone. Wow, that worked amazingly fast.   Staring closely at the stems, flowers and leaves, I noticed some small soft-bodied slightly fuzzy beige larvae scattered around blackish aphid remains.

The green lacewings had come and laid eggs that hatched into starving larvae have been having a field day.   A few are still on some of the milkweeds.   The green lacewing larvae are referred to as aphid lions or wolves since they can bite humans.   The humans that have experienced this have perfectly logical explanations.   The little voracious larvae are just so hungry or they may be very upset that a finger is competing with them for their food.   You must look at this from the perspective of a green lacewing larva. They only have 2 to 3 weeks to eat before they spin little cocoons and emerge as adult lacewings about two weeks later.  Oh well.   These beneficial bugs devour spider mites (yes), leafhoppers, thrips, whiteflies, and other soft-bodied bugs.

Unfortunately they also eat Monarch eggs, but since I have had no Monarchs fluttering about lately, I shall leave the milkweeds to the green lacewings.   They cleaned house and eliminated aphids on seven milkweed plants. These milkweeds, as well as my native green antelope horn milkweeds (Asclepias viridis) are in the Monarch corridor that follows a broad path along both sides of Interstate 35 that traverses Oklahoma north to south.   All the milkweeds should be ready for the Monarch migration this fall as the butterflies flutter south.

The Deck, A Work in Progress

I hope we have cool rain to go along with the dry hot temperatures until then.   If so, the deck may be done by Thanksgiving. Wait.   I could move the Mexican marigold to the deck.