Row by Row Episode 143: A Comprehensive Approach for Managing Squash Pests
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Integrated Pest Management Strategies for Squash Pests
Integrated Pest Management (IPM) is defined as an ecosystem-based approach for long-term management of pests. These approaches usually include a combination of strategies that include biological controls, rotation, sanitation practices, and growing pest or disease-resistant varieties. This way of managing garden pests considers the life cycle and biology of the pest so that populations are managed to an acceptable level that will minimize damage to plants or fruits. Below you'll find IPM strategies for managing a couple of the most difficult squash pests in the vegetable garden.
Squash Vine Borer
Squash Vine Borers are one of the most problematic pests for summer squash plants. The adults exist as a clearwing moth, but the larvae is the life stage that does the damage. Eggs laid by the adult will hatch in 10-15 days and the newly hatched larvae will begin to "bore" into plant stems. The affected part of the plant will usually die quickly as the vascular tissues are damaged by the larval feeding.
Squash Vine Borer eggs can overwinter in soils and hatch the following spring when temperatures warm. Tillage is one method to minimize the damage by the overwintering eggs, as it will disturb the eggs and reduce the hatching success rate. Sanitation is also an important practice to manage SVB populations. Be sure to remove all the crop debris from squash plants each season. Only compost the debris if your compost pile gets hot enough to kill any eggs that may remain.
Modifying planting times will also help to control Squash Vine Borer. In the southern states, planting early will help to get strong plants growing before the egg-laying window occurs. In the northern states, planting later and after the egg-laying window will minimize damage. Try not to plant summer squash in the same location in consecutive years, and practice a three-year rotation if possible. If your insect pressure from squash pests is very high, you may consider skipping planting in a given year to reduce the pressure for following years.
Chemical treatment options include spinosad and pyrethroids. Spinosad is an organic option and works well to kill any worm or insect larvae that feeds on plants or fruits. Start spraying when plants are small and at least once a week to kill the larvae before they enter the plants. Once the larvae are inside the plant, they're tough to kill because they're shielded. A pyrethroid like our Bug Buster II is a conventional option for controlling squash pests. It will actually kill the adults and keep them from laying more eggs. With either option, be sure to apply late in the evenings so that pollinators are not affected.
Squash Bugs
Squash Bugs can be problematic on a wide range of cucurbit species including summer squash, winter squash, melons, and more. As opposed to Squash Vine Borers where the larvae do all the damage, mature adults are the culprits within a Squash Bug population. The adults have piercing mouthparts that they use to feed on the stems of the plants. They suck the sap and inhibit the vascular tissues of the plant, often causing eventual demise. One adult will lay 15-40 eggs at a time and the eggs usually hatch in 1-2 weeks.
As with all cucurbit pests, sanitation is an easy-practice to minimize damage in future years. Remove all crop debris and burn it if possible. Try to practice a cucurbit crop rotation so that you're not planting any cucurbits in the same spot in consecutive years -- a three year rotation is best. Tillage will also help to reduce the impact of overwintering eggs in the soil where cucurbits were planted the previous year.
Hand removal of eggs is an easy way to reduce Squash Bug impact on a small scale. The copper-colored eggs are easy to identify and are usually found on the underside of the leaves. Use a piece of tape to remove the eggs from the leaves prior to hatching, or brush the eggs into a bucket of water and properly dispose away from the garden. For cucurbit crops that climb, trellising is another easy way to minimize the damage. Squash Bugs tend to do most of their damage at the soil level, so growing vertically and minimizing plant contact with the ground will help tremendously.
Chemical treatment options for Squash Bugs include pyrethrins, oil-based insecticides, and pyrethroids. Pyrethrins (Take Down Garden Spray) and oil-based insecticides (Horticultural Oil, Neem Oil) will damage eggs and kill the newly hatched larvae so that they don't become reproductively-mature adults. These organic options, however, will usually not kill the adults that are doing the damage. To kill the adults, a conventional option like our Bug Buster II is necessary.
Show and Tell Segment
On the show and tell segment this week, the guys discuss a few cherry tomato varieties that work great for growing in hanging baskets or patio pots. These varieties are a part of the "Little Birdy" series and include Red Robin, Rosy Finch, and Yellow Canary. Each variety in this series produces a dwarf determinate plant that only gets 8-12" tall and doesn't require trellising.
They also discuss some new varieties of tomatoes that they're trialing this year in their vegetable gardens. These varieties are improved, virus-resistant versions of several popular varieties which include Celebrity, Better Boy, and Big Beef Tomato. The new "plus" version of these varieties includes resistant to Tomato Spotted Wilt Virus which can be especially problematic in hot and humid growing conditions.
Viewer Questions
For the Q&A segment this week, the guys answer questions about possible cross-pollination with tomatoes, growing corn on double rows, and watering sweet potatoes. They explain that since tomatoes are a self-pollinating plant, cross-pollination is usually not a huge concern. However, some cross-pollination could occur from pollinators feeding on flowers from multiple varieties in the same area. This would not affect the fruit, but would affect the seed if one was saving seeds from open-pollinated varieties to plant the following season.
They discuss optimal spacing for sweet corn and that the traditional row spacing is 30-36" between rows. If planting corn too closely, the foliage can prevent pollen from reaching the silks that are beneath the leaves. Travis mentions that he has seen corn planted on double rows with 30-36" between each double row, and that this may be a great option to maximize growing space in smaller gardens.
Travis mentions that he does use drip tape irrigation on sweet potatoes, but does not bury it initially like he does with most other crops he grows. He places the drip tape on top of the soil and plants the sweet potato slips alongside the emitters which are located every 1' along the tape. When the plants start to grow, he then "hills" the sweet potato plants which also serves to bury the tape. This technique allows the tape to feed the plants adequately, but keeps the soil from being too wet around the sweet potatoes themselves.