Del Voight – Penn State Extension
Scouting is a process that requires that the crop producer physically view fields to determine the need for activity. Proper timing of the scouting activity is critical to controlling a pest before harm is done to the crop. For treatment options, rates per acre, harvest restrictions and other information refer to the Agronomy Guide for specifics.
Here are some thoughts for key spring pests to consider.
The alfalfa I viewed in the Lebanon Area had 6-8 inches of growth as of last Friday. This season is advanced due to the heat accumulation being rapid this spring. In my office we have 230 heat units that apply to weevils so in the next few days they will enter a key time to assessing populations in your fields. Consult the PAPIPE system for your local information on weevil activity. I have been checking fields for the last two weeks and noted damage on all fields. Last week I would estimate about 15% damage far below economic thresholds weevils are small mostly 1 and 2nd instars. The larve are still small but will feed rapidly particularly if the weather warms. Scout fields that have a southern exposure. One can use a can or a sweep net to collect weevils and assess populations A factsheet on weevil threshold and product selection can be obtained through the CMEG website. http://ento.psu.edu/extension/factsheets/alfalfa-weevil
Timothy mites are active right now and at the time of your receiving this letter you should have been out looking at the Timothy stands and observing if treatment is necessary. I have heard numerous reports of large populations to our south so it is important to get out and assess timothy stands now. If you see a droughty appearance most likely the mite is causing that appearance. I have found a 30-40 power hand lens to be enough to see the mites moving on the surface of the leaf. We were had plenty of time to react to them last year by spraying for this pest but this year they are multiplying much quicker so it is more critical this season than last. Time treatments to three weeks after green up(this is about now in my area). This should occur about the middle of April in normal years this year I think we are a week or two before that timing. Again a factsheet is available on what to look for and how to properly control the pest on the CMEG website. http://ento.psu.edu/extension/factsheets/cereal-rust-mite
Diseases can severely impact small grain yields. I have identified the growth of Septoria in fields in Lebanon County. As the small grains move into GS 6 and 7 it is imperitive that growers determine the presence and movement of disease up the plants leaf system from ground to top to determine the need to spray. Refer the the Agronomy Guide for specifics on how to properly determine the need to treat for these diseases. I have heard growers including a fungicide with a nitrogen application. We did a couple of year sof work applying extremely early and did not see enough yield benefit to justify spraying. I would discourage this treatment and rather have them look for the presence of aphids, cereal leaf beetles and other insect pests . It appears from my scouting that we have more of a presence of insects than diseases as of today. In the last two years Dr. Collins has shown through the On Farm Network that the GS 8-9 treatments did have a response depending on the level of disease. This again points to one scouting for the presence of the disease before applying a pest management tactic.
Corn and Soybeans
While we have not yet begun the trapping program for cutworms I would expect that we will see the peak egg laying time moved up from previous years. I typically see cutworms about the second week of April but given the weather conditions this spring we could see them earlier. With the amount of egg laying sites that are attractive to both cutworms and armyworms I would not be surprized if we see these pests at economic levels if the weather continues warm and dry. Again the PAPIPE system is a great site to monitor these pests and determine the best time to scout for them. http://extension.psu.edu/pa-pipe