Continue to sample fall planted fields for diamondback and cabbage looper larvae. We can find economic levels of both insects in recently planted fields. If both species are present, Avaunt (3.5 oz/acre), a Bt, Proclaim (3 oz/acre), or Spintor (4-5 oz per acre) will provide control. If cabbage looper is the predominant species, a pyrethroid or Confirm (8 oz/acre) will also provide control.
Be sure to sample fields carefully for corn earworm, lygus and stinkbugs. A treatment should be applied if you find one corn earworm per 6 foot of row or 15 tarnished plant bugs and/or stinkbugs per 50 sweeps. Lannate, Mustang or Capture can be used to control all 3 insects on lima beans. Spider mites are still present in drought stressed fields. Kelthane or Capture will provide control. If Capture is used for insect control, Kelthane should be considered for mite control to provide a rotational material.
At the present time, all peppers should be sprayed on a 7-day schedule for corn borer, corn earworm, and beet armyworm control. Orthene or Address will not provide satisfactory earworm control. A pyrethroid or Lannate will be needed for earworm control. If beet armyworms are present, Avaunt, Spintor, Confirm or Lannate will provide the best beet armyworm control. Depending on the pest complex present, a combination of products will be needed.
Processing snap beans in all areas of the state should be treated at the bud and pin stages for corn borer control. Orthene or Address should be used at the bud and/or pin stages for corn borer control. In all areas, a pyrethroid should be combined with Orthene at the pin spray for earworm control. After the pin stage, Lannate, Capture or Mustang should be used. Sprays will be needed on a 5-day schedule from the pin spray until harvest. Since this can change quickly, be sure to check our website for the most recent trap catches and information on how to use this information to make a treatment decision in processing snap beans (http://www.udel.edu/IPM/traps/latestblt.html and http://www.udel.edu/IPM/thresh/snapbeanecbthresh.html). You should treat fresh market snap beans for corn borers on a 7-day schedule from the pin stage until harvest. Lannate, Capture or Mustang should be used.
Fields should be scouted at emergence for webworm and beet
armyworm larvae. Controls should be applied when worms are small and before
they have moved deep into the hearts of the plants. Also, remember that both
insects can produce webbing on the plants. Since beet armyworms are more difficult
to control and populations are high in
Fresh market silking sweet corn should be sprayed on a 2-3-day schedule in all areas of the state. Since this can change quickly, be sure to check our website for the most recent trap catches and information on how to use this information to make a treatment decision in fresh market sweet corn.
- Kate Everts, Extension Vegetable Pathologist, University of
Latest EFI values from local weather stations
Any questions please call (410) 742-8788
EFI Values (Environmental Favorability Index)
Do not use MELCAST if there is a disease outbreak in your field, it is a preventative program.
Charles Co. 0 0 0 0 0 0 0
Collins Farms 1 3 2 1 1 1 1
Vincent Farms 1 3 4 1 1 1 1
White Marsh 0 0 0 0 0 0 0
The first fungicide spray should be applied when the watermelon vines meet within the row. Additional sprays
should be applied using MELCAST. Accumulate EFI (environmental favorability index) values beginning the
day after your first fungicide spray. Apply a fungicide spray when 30 EFI values have accumulated by the
weather station nearest your fields. Add 2 points for every overhead irrigation. After a fungicide spray, reset
your counter to 0 and start over. If a spray has not been applied in 14 days, apply a fungicide and reset the
counter to 0 and start over. The first and last day listed above can be partial days so use the larger EFI value
of this report and other reports for any specific day.
If, for some reason, a serious disease outbreak occurs in your field, return to a weekly spray schedule.
More detailed information concerning MELCAST and sample data sheets are available on the web at http://www.agnr.umd.edu/users/vegdisease/vegdisease.htm.
Field Crop Insects
We are starting to
find a few fields with economic levels of corn earworm larvae, especially
irrigated fields. In
Therefore, all fields should be scouted for pod feeders as soon as blossoms are present. Since earworms can also act as defoliators, a treatment may be needed if 30% of the plants are defoliated prebloom or 15% of the plants are defoliated during bloom. The treatment threshold for pod feeding is 3 per 25 sweeps in narrow fields and 5 per 25 sweeps in wide row fields (20-inches are greater). A drop (shake) cloth can also be used to estimate populations. The drop cloth should be placed between 2 rows and then the plants are shaken over the cloth in 6 foot of row. A treatment is needed if you find 1-2 larvae per foot of row. When possible, treatment should be delayed until at least 1/3 of the worms at least 3/8-inch long. In addition, watch for diseased worms since the same diseases that attack green cloverworm can also help to reduce earworm population.
The following materials will provide corn earworm control in soybeans: Ambush, Asana, Mustang, Pounce, Warrior (all pyrethroids) or Larvin. If population pressure is heavy, the higher rate of the older pyrethroids will be needed. You should use 2.56 of Warrior and 3.2 oz may be needed if mixed size larvae are present at treatment time.
The dry weather is doing more than reducing yields in
soybeans; it is also showing soybean cyst nematode infested areas very clearly.
Growers and field personnel need to check those yellow areas in fields closely.
Not all that stunting and yellowing is mites or manganese deficiency. I am also
finding soybean cyst nematode in some spots as well. What is confusing is that
at first examination mites are very easily found, but SCN is also present. High
initial cyst numbers at planting combined with the dry weather has produced the
stunted yellow areas when you can find cysts on the roots. That brings up the
next point that during weather like this it is very hard to get a shovel or a
soil probe into the ground. This makes finding the cysts on the roots very hard
unless you are experienced at finding them in the field. If in doubt, take a
soil test and submit it for an SCN test at the
Wicomico Farm & Home Show
Week of August 8
Highs Ranged from 97°F on August 13 to 83°F on August 8 & 9.
Lows Ranged from 74°F on August 14 to 55°F on August 8.
85 °F average for the week.
(Soil temperature taken at a 2 inch depth, under sod)
Web Address for the U of D
Extension Associate-Vegetable Crops
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