STRAWBERRY VARIETY PERFORMANCE IN A MATTED ROW SYSTEM IN NORTHERN NEW
ENGLAND
by David T. Handley, James F. Dill, Univ. of Maine Cooperative Extension
Strawberry production in northern New England is limited by a relatively short growing season, severe winter conditions, and the root rot disease red stele (Phytophthora fragaria). Nearly all the fruit is sold fresh, either as "pick-your-own" or at nearby farm markets, making high fresh fruit quality essential. There are presently no strawberry breeding programs in the northern New England region. Thus introductions from breeding programs in other regions must be tested in order to evaluate their adaptability and performance under New England growing conditions and cultural practices.
Materials and Methods:
The trial was established at Highmoor Farm, part of the Maine Agricultural
and Forestry Experiment Station, in Monmouth, Maine. Fourteen strawberry
varieties were planted from dormant crowns on May 17-18, 1999 (Table 1).
The silt loam soil was amended with 10-10-10 fertilizer at a rate of 500
lb. per acre prior to planting. The plots were established
as narrow matted rows. Crowns were initially planted one foot apart within
rows, with four feet between rows. Flowers were removed during the
planting year, and runner plants were allowed to root to fill out the rows
to a width of two feet. Each plot was 20 feet long. Each variety/treatment
was replicated four times in a randomized complete block design.
The plots were sidedressed with 10-10-10 fertilizer at a rate of 200 lb.
per acre on 3 August, and straw mulch was applied over the planting for
winter protection on 2 December. The mulch was raked off of the plants
on 23 March 2000. Calcium nitrate was applied over the plants at
a rate of 80 lb. per acre on 5 May. The planting was sprayed twice
with a combination of recommended fungicides and insecticides during the
bloom period to control fruit rots, tarnished plant bug and strawberry
bud weevil. Harvest began on 27 June 2000 and continued twice weekly
through 14 July. Fruit was harvested from each plot, graded, counted
and weighed. Data was subjected to Analysis of Variance and mean
separation using the test for Least Significant Difference.
Results:
Two of the varieties planted, Allstar and Annapolis, were eliminated
from the trial due to very poor establishment, probably the result of storage
problems with the crowns prior to planting. The planting year of
the trial was characterized by drought, resulting in many plots being poorly
filled at the end of the season. This very likely lowered yield performance.
The cultivars Mesabe, Brunswick and Mira produced the highest yields of
marketable fruit in this trial (Table 2). Cavendish, Sable, Jewel,
Cabot and Mohawk produced acceptable yields. Evangeline, Northeaster, Honeoye,
and Winona produced relatively low yields. Cabot produced the largest
fruit in the trial, followed by Cavendish, Brunswick, Mohawk and Jewel.
Based on the first year of harvest in this trial, Mesabe, Brunswick and
Mira appear to be promising new cultivars for the northern New England
climate, producing very good yields and having good fruit quality characteristics
(Figure 2). Cavendish and Jewel continue to perform well in this
region, where they have become commercial standards. Sable appears
to be a promising new early ripening variety for the region, and Cabot
offers growers a very large, late ripening berry which may find a specialty
market. Northeaster and Honeoye performed poorly in this trial,
unlike previous trials in this region. This is likely due to drought
stress during the establishment year.
Table 1. Origins and characteristics of 12 strawberry varieties planted in 1999 at Monmouth, Maine.
Variety
Origin
Season Disease
Resistance
Mesabe
Minnesota Mid-late
Red Stele, 5 races; Leafspot
Brunswick Nova Scotia
Midseason Red stele, 3 races; Leafspot
Mira
Nova Scotia Midseason
Red stele, 3 races; Leafspot
Cavendish Nova Scotia
Midseason Red stele, 3 races; Leafspot
Sable
Nova Scotia Early
Red stele, 3 races
Jewel
New York Midseason
None
Cabot
Nova Scotia Late
Red stele, 3 races
Mohawk
USDA-ARS Early
Red Stele, 5 races; Verticillium,
Evangeline Nova Scotia
Early
Red stele, 3 races
Northeaster USDA-ARS
Early
Red stele, 3 races; Leafspot
Honeoye
New York Early-mid
None
Winona
Minnesota Late
Red stele, 5 races
Table 2. Yield characteristics of 12 strawberry varieties harvested in Monmouth, Maine 2000.
Variety
Kg/Plot
Lbs./Acre Grams/Berry
Peak Harvest
Comments
Mesabe
13.7
16,406
11.2
7/5
Sweet, juicy, soft
Brunswick 13.2
15,845
12.4
7/5
Firm, dark, good flavor
Mira
13.1
15,676
9.4
7/5
Sweet, soft
Cavendish 11.2
13,471
14.0
7/5
Odd color pattern, sweet
Sable
10.3
12,327
10.4
6/27
Soft, sweet
Jewel
9.3
11,195
12.1
7/5
Attractive, sweet
Cabot
8.5
10,008
20.7
7/5
Very large, rough, sweet
Mohawk
8.1
9,681
12.3
6/27
Small, sweet, dark
Evangeline
6.5
7,846
10.0
6/27
Small, tart
Northeaster 5.4
6,441
11.5
6/27
Strong, odd flavor
Honeoye
5.2
6,305
11.4
6/27
Poor flavor
Winona
4.9
5,837
10.5
7/5
Rough, soft, mild
LSD 0.051 3.8 3.0
1 Data within a column must differ by this much to be considered statistically
different according to the test for Least Significant Difference (95% confidence
level).
2 Numbers extrapolated from small plot data. Yields can vary
greatly from site to site. These numbers may not reflect actual yields
obtained in grower fields.
NEW ENGLAND FARMERS DIRECT MARKETING CONFERENCE
This regional conference will be held at the Holiday Inn and Conference
Center, Manchester, N.H., on Feb. 26,27 and 28, 2001. Whether you're a
seasoned farm direct marketer, are dreaming about being one or are somewhere
in between, you'll leave this conference with your head full of ideas.
There will be 24 different sessions divided into the following tracks:
roadside stands and pick-your-own; farmers' markets; specialty foods and
processing; beginning farmers; and AG-tourism. For registration information,
call Charlie Tacet, (413) 529-9232.
FACT SHEET: PEST MANAGEMENT FOR VEGETABLE BEDDING PLANTS
A new 15-page fact sheet by Leanne Pundt, UConn Extension and Tina
Smith, UMass Extension is now available. It contains information on managing
plant height, diseases, insects and mites, as well as tables listing labeled
insecticides, fungicides, and biological controls. Includes 10 color pictures.
Contact me for a free copy.
FUNGUS GNATS IN THE GREENHOUSE
(adapted from factsheet above, and tri-state greenhouse IPM workshop
2000)
Fungus gnat larvae feed on decaying organic matter and often injure
seedlings by feeding on young roots and stems of plants. This feeding provides
an entry for diseases. The larvae are translucent white and legless with
a shiny black head. They are 1/4 inch long when mature. Fungus gnat adults
are 1/8 inch long, mosquito-like, with long antennae and clear wings that
have Y-shaped veins. They are weak fliers and can often be seen resting
on or walking over growing media and foliage. Each female can lay up to
300 whitish eggs, in clusters of 20, on the soil surface or in crevices
in the potting media. Eggs hatch in about 6 days and then larvae feed for
12 to 14 days before changing into pupae for 5 to 6 days. Adults live for
up to 10 days. In most greenhouses the lifecyle will take about a month;
at 75 degrees the time from egg laying to adult is about 3 weeks.
Monitor for adults by frequently inspecting yellow sticky cards placed horizontally at the soil line next to the base of plants. Early detection of adults is key to effective biocontrol by timely application of B.t. soil drench (such as Gnatrol) to control the larvae soon after hatch. Remember that B.t. works only on larval stage. It should be applied 4 to 10 days after planting for best effect. The colder the soil the longer the delay. For greenhouse vegetable transplants set in the ground, apply B.t. drench about a week after watering in plants. Raw, peeled potato chunks, one inch in diameter and a half inch thick placed on the soil surface can be used to monitor for larvae, which will congregate underneath. To be effective, B.t. should be applied before large numbers of larvae are present.
Fungus gnats often seek out fresh moist potting soil to lay eggs, attracted to the fermentation process going on. When setting out new plants, the first generation of larvae can be expected 3-4 weeks after planting, although often it is not very noticeable. The second generation 3-4 weeks after that is very noticeable.
B.t. controls fungus gnat larvae but NOT shorefly larvae. Shorefly larvae do not injure plants by direct feeding but they can spread disease. Like fungus gnats, shorefly adults are also about one eight inch long, but they have a more robust body, short antennae and dark wings with light spots. On vegetable bedding plants, shorefly adults can be controlled with repeat applications of neem-based insecticide containing azadarachtin, Azatin XL.
Preventive strategies help minimize fungus gnat and shorefly populations. Thoroughly inspect incoming plant material for infestations. Remove discarded plant material and growing media from the greenhouse and eliminate weeds growing beneath benches. Keep areas below benches free of spilled potting mix, weeds and other debris in which fungus gnats might breed. Eliminate standing pools of water on solid benches, on walks, and under benches by proper grading and drainage and by watering plants in a way that limits runoff. Eliminate algae as best you can. There are commercially available products for treating walks and other surfaces that tend to have algae. Research has shown that fungus gnat problems are most serious in potting mixes amended with composts lacking in maturity (not completely composted). Microbial activity is excessively high in such mixes, and fungus gnats thrive.
HOLD THE DATES...
April 10: Greenhouse IPM 'on-farm workshop', Killdeer Farm, Norwich.
May 22: Strawberry IPM 'on-farm workshop', Norris Berry Farm, Monkton.
(Mention of pesticide brand names is for information purposes only,
no endorsement or discrimination is intended. Always follow the label.)