Rutgers Cooperative Extension
Seasonal updates on diseases, insects, weeds impacting tree fruit and small fruit (blueberry, cranberry, and wine grape). Fruit Pest Alerts are also available via this category feed.
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Peach:
Oriental Fruit Moth: Second generation timings are updated below. Second flight adults are still flying statewide. Treatments for the second generation have just finished in southern counties, and are going on now in northern counties. [Read more…]
Based on our degree-day (DD) model for Sparganothis fruitworm, peak flight and first eggs hatched events are expected at around 884 and
Sparganothis degree-day model benchmarks
895 DD, respectively (see chart). As of June 20, Sparganothis has accumulated 1022 DD (using March 1 as biofix) or 883 DD (using April 15 as biofix; a biofix more realistic to New Jersey practices). Based on the April 15 biofix, we are at peak flight activity and eggs should start hatching within the next few days. Larval injury to fruit usually begins after the eggs hatch. If treatment is required (based on pheromone trap counts), sprays should be applied two weeks after peak moth flight (i.e., 1st week in July) and/or earlier (i.e., next week) if populations are unusually high. When bees are present, your option is to use an insect growth regulator such as Intrepid. Our “standard” recommendation has been, however, to wait until bees are removed to apply an insecticide. Your post-bloom options include Diazinon, Altacor, Delegate, Exirel, or Intrepid. Timing of insecticide application is critical; so, if needed, do not wait longer than July 5 to manage this pest.
Peach:
Oriental Fruit Moth: Second generation timings are updated below. Second flight adults started this past week in southern counties and are about to start this coming week in northern counties. According to the model, treatments for the second generation should be going on now in southern counties, and should start next week in northern counties. [Read more…]
Recent Rain Patterns and Insecticide Use:
Given our recent periods of rainy weather, many growers are questioning the need for repeated applications, and the weatherability of the materials already applied. Dr. John Wise at MSU has been studying the residual properties of insecticides for a number of years. [Read more…]
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Cranberry beds are in bloom. If insects have been effectively managed prior to bloom, we recommend no sprays at this time. A reminder: when bees are present your only choices of insecticides are insect growth regulators (IGRs) such as Intrepid 2F or Bt products such as DiPel.
During bloom we recommend monitoring insect populations using pheromone traps. Pheromone traps should be used particularly to monitor activity of Sparganothis fruitworm and blackheaded fireworm, two key pests in New Jersey.
Sparganothis fruitworm– Adult flight should have started a few weeks ago and we will be at peak flight activity by next week (see DD model
Sparganothis fruitworm adult
below). Damage by the second generation larvae begins after the eggs hatch, usually 9-12 days after they are laid. These larvae will feed on foliage and fruit. Larvae will partially feed on berries, causes scoring of the fruit. However, particularly on Ben Lear, larvae may feed inside the fruit. Insecticide treatment should target small larvae. Pheromone traps can be utilized to time insecticides sprays. If treatment is required, sprays should be applied two weeks after peak moth flight and/or earlier if using an IGR. If trap counts indicate a low population that requires management, a single insecticide application may be made post-bloom. If trap counts are high, then an early application of an IGR may be used when the first eggs start to hatch. This would be followed by a second application soon after bloom. Your post-bloom options are Diazinon, Altacor, Delegate, Exirel, or Intrepid.
As indicated above, controlling fruitworm populations is often very difficult and many require multiple applications depending on pest pressure. Sparganothis fruitworm populations in Massachusetts are resistant to organophosphate insecticides (e.g. Diazinon, Lorsban). Thus, organophosphates should be used with care, i.e., always rotate insecticides with different modes of action. Organophosphate insecticides will also negatively affect natural enemy populations. Delegate, Altacor, and Exirel are insecticides belonging to relatively new modes of action; these are registered against fruitworms and can be used as an alternative to organophosphates post-bloom.
Degree-day model for Sparganothis fruitworm
The figure details life history benchmarks of interest for Sparganothis fruitworm and associated degree-day estimates from March 1(credit:
Sparganothis degree-day benchmarks
Elissa Chasen and Shawn Steffan, USDA-ARS and UW Entomology). Flight initiation is predicted around 595 DD, at a lower temperature threshold of 50°F. Based on this model Sparganothis fight was initiated in our region (Chatsworth, NJ) about a week ago. So far, we have accumulated (starting April 15) 688 DD, which means that egg laying has just started (depending on the DD accumulations specific to your farm); however, eggs are not expected to hatch until later this month. Also, a reminder that a single insecticide application aimed at Sparganothis larvae will likely have the greatest effect if it is timed between the beginning and the peak egg-hatch/larval-emergence, which is approximately 895-1,400 DD. I will keep you updated on these DD predictions as the season progresses.
