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* Black
Vine
Weevil
* Spider
Mites
* Western
Raspberry Fruitworm
* Obliquebanded
Leafroller
* Armyworms
and Cutworms |
* Botrytis
Fruit Rot
* Spur
Blight |
Biology
Black Vine Weevil (BVW) (Decision
Making Guide) (Images)
BVW are usually just beginning to emerge from the soil during mid
to late May. When weevils first emerge, their bodies have not fully
hardened and they are
quite soft to the touch.
Spider Mites (Decision
Making Guide) (Images)
Spider mites can begin to increase at this time of the year but
this is quite variable from one field to the next. They are more
commonly found on older
or mid-shoot leaves on fruiting canes, rather than on primocanes during the
early summer. White speckling or stippling of the upper leaf surface is a sign
that mites are present and feeding.
There are no scientifically determined treatment thresholds for
spider mites at this point in the season. Factors which influence
treatment decisions include; spider mite density, abundance of predators,
population trends, damage to foliage, weather conditions, and miticide
pre-harvest interval (PHI). Spider mite increase is favored by hot,
dry dusty conditions.
Western Raspberry Fruitworm (Decision
Making Guide) (Images)
Adult, egg and larval stages of this insect may all be present
during this period, particularly if beetles were present and were
not treated prior to
bloom. Adult beetles feed on the flower parts and young larvae feed on the
developing fruits. These larvae can contaminate harvested fruit, but are very
difficult to control as they feed within the berries. Control at this time
is complicated due to presence of honeybees and multiple stages of the insect.
Armyworms and Cutworms (Decision
Making Guide)
A variety of caterpillars which feed on foliage can be present
during mid-summer. Their feeding does not usually cause significant
damage to plants, but they
can be serious harvest contaminants. Most of these are nocturnal and they are
very difficult to detect within a thick raspberry canopy. Often, growers are
not aware of their presence until harvesting begins.
Obliquebanded Leafroller (OBLR)(Decision
Making Guide) (Images)
Most OBLR are now in the late larval or pupal stages, preparing
for their metamorphosis into adult moths which start flying in
June. OBLR moth flight doesn't usually
start until late May, with peak catch occurring in late June and early July.
The larval stage of this insect is the dominant stage found during April and
May.
Botrytis Fruit Rot (Decision
Making Guide) (Disease
Cycle) (Images)
Initial infection of fruit begins during early bloom when botrytis
spores are dispersed by wind and splashing water to infect developing
flower parts. These
early infections remain inactive (latent) until fruit develops and conditions
are favorable for the fungus to further infect the fruit, causing gray mold
on infected berries. This mold releases spores which cause additional fruit
and cane infections.
Spur Blight (Decision
Making Guide) (Disease
Cycle) (Images)
Primocanes are commonly affected by this fungus disease which overwinters
on infected canes produced the year before. Spores released from
lesions on these
canes can infect floricane and primocane foliage, usually appearing as a brown,
wedge-shaped lesion. This is the symptom that may be seen at this time of the
season. The fungus then moves through the leaf and petiole and is most apparent
as a purplish/brown lesion around the bud on the lower portion of primocanes.
This symptom on primocanes may not be seen until mid-harvest or thereabouts.
Monitoring
Mid-May
Beating Tray Sampling Method
-
Pest and Beneficial Insects
- Use beating tray to survey
the canopy for several
insect pests that can directly damage fruit or may pose problems
as harvest contaminants.
- Visit
several sites in each field.
- At each site, take ten tray samples
and record the total number
of insects dislodged from foliage.
- Hold tray about one foot below trellis wire within canopy
and shake foliage by grasping wire with hand and shaking, or
striking top wire three times with rubber sprayer hose to dislodge
insects.
- Alternate samples between rows and check about every ten feet
down the row.
The following insects are typically found using the beating tray
method.
- Beneficials
-
Minute pirate bugs
- Lady beetles
- Stethorus beetle*
*These are the most important insects which should be recorded.
Western Raspberry Fruitworm (Decision
Making Sheet) (Images)
- Continue
monitoring raspberry fruitworm beetles.
- Optimum timing for control is prior to bloom, but controls
may be justified if beetles persist.
- The beating tray is a good tool for dislodging them from foliage.
- There are no thresholds established.
- Some level of control is probably achieved by clean up sprays
applied in most fields in late June or early July.
Obliquebanded Leafroller (Decision
Making Sheet) (Images)
- Record
number and approximate size of leafrollers when found
on beating trays.
- Sprays directed at the worm stage in late May are probably
too late to control any significant percentage of the larval
population.
- Place
obliquebanded leafroller (OBLR) pheromone traps out
in the field in mid-May. These traps use a sex attractant to
monitor the adult male OBLR. They are a useful tool for determining
peak adult activity and can help determine key periods to monitor
for the second generation caterpillar stage which can be a harvest
contaminant. Trap catch cannot be used to accurately reflect
OBLR population size or expected damage from this insect.
- Hang traps from the top trellis wire near canopy height within
ten feet of the windward edge of a field.
- One or two traps in a field can provide meaningful pest management
information.
- Check
pheromone traps weekly starting in late May and throughout
June.
Black
Vine Weevil (Decision
Making Sheet) (Images)
- Expect to start seeing adult BVW in beating tray samples late
in May.
- The numbers will likely increase significantly by the middle
to latter part of June.
Spider
Mites (Decision
Making Sheet) (Images)
- Examine
leaves using a 10X handlens for presence of mites and
mite predators.
- Collect ten leaflets per site from a minimum of four sites
distributed throughout a field.
- Count the number of spider mites and mite predators and record
information at each site.
- Make
note of the predominant mite stage (recent hatch, mixed,
or mostly adult).
- Estimate
spider mite egg density by observing the ratio of
eggs to spider mites on a leaf or two.
- Mite populations can increase rapidly.
- The following should be recorded:
- Spider mites
- Predatory mites and eggs
- Stethorus adult
- Stethorus larvae
- Minute pirate bug
Fruit,
Cane and Foliar Diseases (Decision
Making Guide)
- As you are collecting leaves for mite sampling, note how may
are infected with yellow rust aecia and the degree of infection.
Both aecia and uridia stages may be present at this time.
- Note if rusted leaves are on fruiting canes or on primocanes.
A fungicide may be necessary to protect new growth if the disease
is found at most sites in a field and wet weather persists. The
preferred timing is to apply a fungicide prior to the presence
of the summer uridia stage, usually late April to early May.
- Check floricane and primocane foliage for brown wedge-shaped
lesions, characteristic of spur blight. Fields with a history
of spur blight infection or with current season infection should
be treated with a fungicide again in early bloom. This treatment
when necessary can be scheduled with the Botrytis fungicide program.
Most fungicides that control botrytis will also help to control
spur blight, however Ronilan is not active against the spur blight
pathogen.
- There is no monitoring procedure for Botrytis fruit rot at
this time of the year. A protectant fungicide is usually necessary
in the early bloom stage (10% bloom) in established, bearing
fields. This is usually followed within 14 days with a second
protectant fungicide application. Subsequent applications depend
largely on incidence of fruit infection, method of irrigation,
and weather conditions.
June
This is a critical period for insect and
spider mite monitoring because results from sampling will help
determine specific pre-harvest spray needs and timing.
Harvest
Contaminants
- Continue
beating tray samples to monitor weevils and
miscellaneous cutworms.
- BVW counts tend to increase in mid to late June as more adults
emerge from the soil. The best time of day to use a beating tray
is early in the morning before weevils move down from the canopy
or on cool, cloudy days when they are more likely to remain in
the canopy. If you are sampling with a beating tray primarily
to measure weevil activity, sampling at night when weevils are
most active will usually provide the highest counts.
- Most of the feeding damage from adult weevils is in the center
of the canopy around the wire.
- As
you collect leaves for mite counting, make a note of
whether there is notching of leaves.
- Take
extra samples near field borders, particularly
if field is adjacent to a known weevil source such as a woodlot,
older strawberry field or rhododendron planting.
- If you find just a few weevils at each site, treatment is probably
warranted.
- Where
weevils require treatment, attempt to time sprays
three to four weeks after peak emergence which is before
most egg laying occurs (see weevil egg-laying chart).
- If
there is no feeding damage and weevils are not detected using
beating trays, a specific weevil spray may not be necessary.
This may allow you to use a "softer" clean-up spray
which may not destroy as many mite predators.
- Pay close attention to miscellaneous cutworm larvae at this
time as well. A few small worms occasionally detected in a field
may indicate a major hatch is occuring.
Obliquebanded
leafroller (Decision
Making Sheet) (Images)
- Check
leafroller traps weekly and record the catch.
At about ten days after peak trap catch, it is time to monitor
caterpillars in the field as described in the pre-bloom section.
- Examine a maximum of five shoot tips ber hill from 20
hills per site.
- Check
four to five sites in the field, each representing
about an acre.
- Record
the total number of infested hills and divide
by the total number of hills inspected.
- Multiply this number by 100 and you have the percentage of
leafroller infested hills.
- If 10% or more are infested, a treatment may be necessary.
Spider
Mites (Decision
Making Sheet) (Images)
- Continue
sampling leaves for spider mites and their
predators at least every two weeks.
- Compare
counts of both spider mites and mite predators
to earlier sampling results.
- Trends in populations are very important when determining if
treatment is necessary.
- Revisit sites where mites were detected at the previous visit.
- A spider mite spray may be necessary before harvest if:
- spider mites are approaching ten/leaflet or more and
there are few or no predators;
- spider mites are increasing and there are numerous eggs
as well;
- spider mites are increasing and predator:prey ratio is
less than 1:10;
- miticide PHI is three or more days and population is
building.
- A spray decision can be delayed if:
- available miticide has a short PHI (one to two days),
allowing for treatment during harvest if it becomes necessary.
- spider mites are diffucult to find
Botrytis
Fruit Rot
(Decision
Making Sheet) (Images)
- No specific monitoring of fruit until first fruit starts to
ripen in late june.
- Depending on weather conditions, a third and possibly fourth
fungicide application may be necessary. The frequency of fungicide
applications targeting Botrytis is greatest in fields destined
for high-end quality markets, which have a very low tolerance
for diseased fruit.
- Don ot tank mix fungicides with similar modes of action.
- If multiple fungicide applications are made, alternate between
fungicide classed to avoid resistance problems.
Scouting
Report - Bloom/Pre-Harvest (PDF File)
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