Today’s post is from our Biocontrol Specialist, Amara Dunn
Have seed and plant catalogs started arriving in your mailbox, yet? This is the time of year I start thinking wistfully about the arrival of spring. If your spring daydreams include planting habitat for pollinators and other beneficial insects, keep reading for the latest on NYS IPM’s beneficial insect habitat establishment project!
Back in October I described the purpose and design of this project. So what have we learned after the first year? First, here’s a reminder of the different treatments we were comparing. Each treatment involved either direct seeding or transplanting habitat plants, in the spring or the fall, utilizing a different method for weed control.
| Treatment | Fall 2017 | Spring 2018 | Summer 2018 | Fall 2018 |
| A | Herbicide | Herbicide, transplant | Weed 2x | Replace dead plants |
| B | Herbicide | Till, transplant, mulch | Weed 2x | Replace dead plants |
| C | Herbicide | Till, direct seed | Mow 3x | Mow 1x |
| D | Herbicide | Till, plant buckwheat | Mow 1x, till, plant buckwheat | Mow 1x, transplant |
| E – control | Herbicide | Herbicide | Mow 3x | Mow 1x |
| F | Herbicide | Till, lay plastic | Continue solarization | Remove plastic, direct seed |
| G | Herbicide | Herbicide/till | Herbicide 2x, till 1x | Till 1x, direct seed |
And here’s how much time and money we spent on each method during our first year. Each treatment was applied to a total area of 460 ft2 (0.01 A).
| Treatment | Supply costs |
Time (person hrs) |
| A – Spring transplant | $417.12 | 13.2 |
| B – Spring transplant and mulch | $539.29 | 20.4 |
| C – Spring seeding | $17.75 | 4.4 |
| D – Buckwheat & fall seeding | $390.55 | 10.3 |
| E – Control | $2.32 | 2.6 |
| F – Solarize & fall seeding | $148.02 | 10.2 |
| G – Herbicide/tillage & fall seeding | $22.04 | 6.3 |
What did we get for the time and money we invested? Well, the only two treatments that looked anything like habitat for beneficial insects by October were the ones we transplanted in the spring (A and B). And of the two, treatment B looked a lot better because of the mulch we spread around the plants after transplanting to help suppress weeds. Even so, we still hand weeded this treatment (and treatment A) twice during the year. But we got much better weed control in treatment B.
Four and a half months after transplanting, the beneficial habitat plants in treatments A (left) and B (right) were mostly growing well. But there was a big difference in weed control, in spite of similar amounts of time spent weeding each treatment
Direct-seeding in the spring resulted in a few blackeyed Susans by October (and a few partridge peas slightly earlier in the year), but did not look very impressive and had a lot of weeds.
After direct-seeding in the spring and mowing four times during the summer and fall, there were a few blackeyed Susans blooming in treatment C plots.
Of the three methods we used to manage weeds during the season, alternating herbicide applications and tillage resulted in the cleanest-looking plot by October.
A few weeds were present a week after the last time the herbicide/tillage treatment (G) was rototilled. We broadcast, raked, and pressed beneficial habitat seed into these plots.
Solarizing the soil was low-maintenance once the plastic was laid in the spring. We did learn that solarization is not a good strategy if you’re trying to control purselane. It grew just fine under our clear plastic, while most other weeds didn’t. In some places, it probably reduced the efficacy of solarization because it pushed the plastic away from the soil and allowed other weeds to germinate and grow.
In some solarized plots, purslane grew happily under the plastic. Purslane was not a common weed anywhere else in the field during the season.
The two crops of buckwheat we grew in treatment D not only suppressed weeds, but also attracted lots of pollinators and natural enemies to its blossoms before we mowed the crop down to keep it from going to seed.
The buckwheat established quickly and crowded out many weeds. We mowed the first crop in July and re-planted. We had to mow the second crop about 3 weeks before we transplanted (not ideal).
In summary, if one of your 2019 resolutions is to plant habitat for beneficial insects, I have two pieces of advice:
- Spend 2019 controlling weeds. Even where we transplanted, weed pressure was a challenge, and investing in weed control before you plant is worth it!
- If you have sufficient funds and need or want to establish habitat quickly, transplants are the way to go. Mulch will help you with your battle against weeds.
In 2019, we’re planning to keep monitoring these plots. Check back to see how the fall-planted and direct-seeded treatments look in their second year. Most of these methods are expected to take several years to reach their full potential. We will also start counting the insects (and insect-like creatures, like spiders) we find in these plots. During 2018, we already started seeing some beneficial insects showing up in these plots, so I’m looking forward to counting them once spring finally gets here!
Here are just a few of the beneficial insects we spotted in these plots during 2018. Soldier beetles, many hover flies, and lacewing larvae are all natural enemies of pests. We also saw lots of lady beetles and several other types of bees.
Thanks to Betsy Lamb and Brian Eshenaur who are working on this project with me, and to Bryan Brown for doing a weed assessment for us. You can read more about this project and see more pictures from 2018 at Biocontrol Bytes. Subscribe to make sure you don’t miss future updates!
