5/16/12 Weigela Florida ‘Elvera’ Midnight Wine flower buds
5/6/13 Transplanted our Midnight Vine Weigela florida ‘Elvera’ from its original 1gal pot to a 3gal fab pot. Also moved it to a sunnier spot (from corner near Pink Dawn Viburnum to down the pathway closer to the raspberries, in front of the figs.
Apr10,12: Cucumbers wilting again.
Many of our cucumber transplants in the stage 2 (6″) wooden flat (filled with our garden soil) are wilting and declining, just like we lost most of our transplants last year (planted directly into the ground). It started with a couple plants along one edge of the flat, and is progressively affecting more and more plants toward the opposite side of the flat. The soil in the flat is from a different area of the backyard than where we planted the cucumbers last year, but based on the fact that it started on one side of the flat and is sweeping across makes me think it must be some sort of soil-borne organism that’s spreading and affecting the roots. I poured a bit of H2O2 onto the affected soil area to see if it might help. Started more seeds to make up for losses.
Apr18,12 Cucumbers, Tomatoes
Cucumber wilting is continuing to progress across the flat, so I decided to transplant them into flats of commercial potting mix and do some research as to what may be causing this. The wilted plants showed root damage (small stunted limp root systems).
Most wilting (in cucumbers and other members of the squash family) appears to be caused by bacterial wilt spread by the striped and spotted cucumber beetles. To test for bacterial wilt, I read to cut a badly wilted stem just above soil level and squeeze it. If a sticky, oozy substance comes out, it’s bacterial wilt. The slimy substance is blocking the plant’s circulatory system and blocking water uptake.
According to a Utah State University Pests Fact sheet, it is the striped cucumber beetle larva that feeds on the roots and fruits of cucurbits (squashes, melons, cucumbers, pumpkins). Larva of the spotted cucumber beetle feed on the roots of corn, beans, grains and grasses (in early May).
Overwintering adult female beetles are about 8-9mm long (black head, yellow prothorax (segment behind head), and wings with alternating yellow and black stripes) and become active @>50°F. They can fly long distances (100s of miles on wind currents) and feed on weed pollen/nectar before their preferred host plant material is available. They mate in spring and lay hundreds of eggs in moist soil at the base of cucurbit plants, while they feed on the host plants (above ground).
The eggs are oval, yellow orange, and hatch in 7-10 days. Larva are wormlike, 8-13mm long, cream colored body, brown head, and 3 pairs of brown legs. In spring, they feed exclusively on the roots of cucurbits. The second generation larva in late summer also feed on the fruit.
The damaging larva stage lasts about 15 days. Pupa are cream colored, about 6mm long, and look like soft-bodied adults without wings. Pupa stage lasts about 7 days.
One effective method for controlling cucumber beetles is to plant “trap crops” (certain zucchini, pumpkinks, etc) 2 weeks before the main crop to attract and capture the beetles, treating them with insecticides to kill the adult beetles before they lay eggs.
Also effective are row covers that prevent adult beetles from landing on the plants and surrounding soil. Make sure to remove when plants begin to bloom.
Research conducted in Virginia (Caldwell and Clarke 1998) has shown that aluminum-coated plastic mulch significantly reduced numbers of cucumber beetles on plants. These reflective mulches repelled cucumber beetles and aphids and reduced transmission of bacterial wilt and virus diseases.
Also noticed this week that our tomato transplants (transplanted a month ago on 3/18) growing in the Miracle Gro Moisture Control Potting Mix (55 Qt bags purchased at Costco) are paler in color than the tomato plants growing in the box with regular garden soil. This surprises me somewhat as the potting mix contains fertilizer and even iron.
The tomato plants in the potting mix are currently 5″ tall (even reaching to 6″ in the box we keep in the office), while the ones in our native soil are still slightly short of 4″, but darker green and just as healthy looking.
Light could be a factor: The large box with native soil is kept in front of the bed room window, while the flats with the potting mix only get artificial light when they are indoors. In fact, the box in the office (2nd picture below) only has one (2 x 40W bulb) fixture on it, and I noticed today that the plants directly under the bulbs are darker than the ones along the edges. This is also the box where the plants are over 5″ tall.