Sunday, July 3, 2011


Here in my part of the world, gardens have kind of slowed down a touch, due to the extreme hot weather. In other parts of the country, gardens are pretty much in full swing. I decided to take a chance and planted a third crop of Cucumbers, along with some Hubbard Squash, Zucchini and Dills Atlantic Pumpkins.
As a side bar, if you are unfamiliar with the Dills Atlantic Pumpkin, this is the one that regularly produces world record size pumpkins. The current world record was grown in Wisconsin and weighed 1810.5 pounds. The current South Carolina record is 1164 pounds. If you are curious as to your state record, you can find them all here: State Pumpkin Records
In order to grow large pumpkins or any other type of squash and cucumber, you need to be aware of a really boring critter....Melittia cucurbitae or Squash Vine Borer.
This pest ranges from Canada to Argentina, with the possibility of southern states having two broods a year, and is the most serious enemy of squashes,(Summer and Winter) as well as pumpkins and gourds. Cucumbers and melons are less frequently affected. Though they will hit these if hungry enough.
The adult borer resembles a wasp, even though it is a moth. It is about 1/2 inch long with an orange abdomen and black dots. The hind legs are fringed with black and orange hairs.
Eggs are flat, brown, and about 1/25 inch long. The larvae are white or cream colored with brown heads, growing to almost an inch in length.
Beginning in late June or early July, late May in the South, Squash Vine Borer adults emerge from cocoons in the ground. They are an unusual moth because they are a diurnal species, which means they fly during the day, unlike most moths that fly at night.
The female will lays eggs on any and all parts of the plant, except the upper leaf surface. The majority of eggs are laid on the basal stem (plant base). Hatching larvae usually bore directly into the stem and feed internally for about 4-6 weeks, though some may feed externally prior to entering the stem.
The damage they do is caused by the larvae feeding through the center of the stems, blocking the flow of water to the rest of the plant. Plants wilt and usually rot and die beyond the point of attack. The first indication of an attack will be the sudden wilting of a long runner or of the entire plant. Closer observation of a wilting plant often reveals holes near the base of the plant filled with moist greenish or orange sawdust like material called frass, basically, bug excrement.
Once this pest invades your plant, pesticides are ineffective. There are those out there that have had some success when an infestation occurs. You can slit the infested vine lengthwise and remove borers or kill them with a long pin or needle. The slitting operation does not always work because you can miss one or two borers, and the plant is usually too weak to save at that point anyway.
The use of row covers before flower bloom can be effective, unless borers from previous seasons have entered your soil and pupated.
One method that I have heard about, and will try this year, is this,as soon as your vine starts to lay down from the weight of the plant, place aluminum foil on the ground underneath the stem at the base to disorient the arriving moths. This sounds somewhat reasonable, again, as long as the larvae from last year have not entered the vine yet. You can till the soil in late Winter to expose overwintering insects if you have had previous experiences. Rotating squash to another location in the garden each season is another good option.
Insecticides can be also be useful in killing the moths before they lay eggs. Caution should be used however, it will also kill your pollinators. Remember to follow the label directions! Ideally, you will want to monitor for the moths and apply the insecticide after the plant stops flowering. Observation is the key here. Adults make a very noticeable buzzing sound when flying. You can also use yellow trap pans to detect Squash Vine Borer adults. This can be any container (pan, pail, bowl) colored yellow and filled with water. Because Squash Vine Borer adults are attracted to yellow, they will fly to the container and be trapped when they fall into the water.
There are certain squash varieties that offer an apparent resistance to and tolerance of borer attack. Some of these include, Summer Crookneck and Butternut. Some of their favorites include, Hubbard type squash, Connecticut Field Pumpkin, Small Sugar Pumpkin, and Zucchini.
Hopefully you will not have to deal with this pest and can either compete for the worlds largest pumpkin or have enough Zucchini to supply the neighborhood.
Happy Growing!

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