Insect Pest Control in an Early Season
Posted: March 23, 2012
As of current insect observations, yesterday (March 22) was the first day of capturing Oriental fruit moth (OFM) (normally it is around mid-April). It is the second week of collecting redbanded leafroller (RBL) and spotted tentiform leafminer (STL). Since we need at least a couple days of sustained flight to establish a biofix, it is difficult to decide right now if March 23 will be the biofix date for OFM. We will have to wait and see how consistent this trend will remain.
Historically, the bloom of apple trees is the time when both CM and TABM start their first generation flights; however during the 2010 season, which granted us a mid-April bloom of apples, the CM and TABM biofixes were not established until about 2 weeks after the bloom. Although pheromone traps are needed during the entire growing season to assess population levels, the precise detection of initial moth activity during the spring is necessary for better timing of available control measures against those pests. Therefore, this year we again strongly, strongly suggest placing pheromone traps in the orchards much earlier, so the biofixes can be precisely established. A moth count of zero is a number, and actually in certain situations it can be a very good one.
Similarly, the brown marmorated stink bug (BMSB) adults also started early this season and already are leaving overwintering sites and initiating early feeding on available green plants. Unfortunately, the movement from overwintering sites is a very extended process and could last for another 10 weeks. In consequence, while within 2 to 4 weeks the adults could become reproductively active, most likely there will still be plenty of overwintering BMSB adults that still remain in a non-active phase. So at this time, unless strong evidence exists for the actual presence of BMSB in orchards, no specific control measures should be applied. Additionally, our around bloom pest management activities directed against other pest species should provide at least some control of BMSB.
In the next few issues of the Fruit Times Newsletter we will present more detailed brown marmorated stink bug management recommendations based on information generated during last season.
The following updates are normally posted in the April issue of the newsletter but this year we decided to deliver them earlier. Although the early spring timings for insect management activities historically are based on phenological phases of tree development, in such an unusual year as this one, the actual on site monitoring of various pests should be the only valid pest management decision tool.
Protecting Bees and Other Native Pollinators
Although some insecticides are legally allowed as an application during the bloom (with various restrictions), the pest complex that can be controlled during that time period [obliquebanded leafroller (OBLR), European apple sawfly (EAS), rosy apple aphid (RAA), Oriental fruit moth and plum curculio (PC)], in most cases, can also be controlled at other, less controversial timings. Therefore, due to continuous concerns with the possible insecticidal effects on honey bees and other native pollinator populations, we recommend that growers not use insecticides until the bees are completely removed from the orchards. This season especially, due to this unusual weather pattern, our native pollinators may be the best we have for effective pollination of our crops.
Petal Fall Insect Pest Control
Oriental fruit moth, plum curculio, mites, aphids, leafminers, some leafrollers (OBLR) and to some degree scales are the insect pests that normally should be controlled at petal fall. The application of insecticides during the petal fall period still remains one of the most important treatments, setting the tone for the rest of the season. The combination of OFM, PC, European apple sawfly, oblique banded leafroller and redbanded leafroller (RBLR) should be controlled at this time by broad-spectrum insecticides (e.g., organo-phosphates; or neonicotinoids (Assail, Calypso); or Avaunt). Older neonicotinoids (imidacloprid containing products or Actara) applied at the petal fall timing will provide excellent control of aphids and leafminers but they will not control many other pests, although both provide good contact activity against brown marmorated stink bug (if present in the orchard) and some against plum curculio. If only leafrollers, OFM and leafminers are the intended target(s) of the application, then an application of Intrepid, Proclaim, Rimon will also be very effective. With expected, in season increase in usage of broad spectrum, not selective insecticides, the suppression of European red mite population after bloom might significantly help to manage this pest later during the season. Agri-Mek with a penetrant (i.e., oil) applied at petal fall, in most cases still offers excellent control of ERM and STLM, and fair to good control of white apple leafhopper (WALH). Agri-Mek should be applied before the leaves harden off, generally within about 10 days of petal fall. Other acaricides such as Acramite, Envidor, Portal, Kanemite, Nexter or Zeal, although registered mainly for summer mite control, can also be considered for mite control at this time of the season. The ovicidal acaricides - Apollo, Onager (Savey) – can be applied during the petal fall to first cover period. Please see the recommendations in the new 2012-2013 Pennsylvania Tree Fruit Production Guide for rates of all products.
Control of Scale Insects
San Jose scale overwinters as immature blackcaps on the trunks and scaffolds of the tree. The nymphs remain dormant under their waxy covering until the sap begins to flow in the spring, and they continue to feed until bloom. Scales are especially difficult to control on large trees with rough bark. Growers who found fruit infested last fall with scale or who noticed scale infestations during the winter pruning, should apply the appropriate measures during this time of the season. To provide successful control of nymphs an application of oil with an insecticide (i.e., chlorpyrifos, Esteem or Centaur) is necessary at the delayed dormant or early pre-bloom period. If needed, another application of Esteem, Centaur or Movento applied after bloom (up to second cover) also should help in management of this pest. Addition of oil is always necessary with applications of Centaur or Movento, while Esteem can be applied without oil. Similarly to early season mite control, the secret to good scale control is good coverage. Growers should use a minimum of 100 gallons per acre (GPA) or more depending on the size of their trees.
Please remember that the new language on the label for all products containing chlorpyrifos (e.g.,Lorsban) allows for only a single application of per year either as a dormant/pre-bloom or trunk spray during the season.
Seasonal Activity of Fruit Pests
2012 season-weekly captures of adult moths in pheromone traps located at PSU FREC Biglerville, PA (Adams County):
Species 3/16 3/23
RBLR 26 143
STLM - 109
OFM - 3
Key to acronyms: RBLR - redbanded leafroller; STLM - spotted tentiform leafminer; OFM - Oriental fruit moth.
Degree Day Table
Accumulated degree-days base 43°F from Jan 01 for each reported year (courtesy of SkyBit, Inc.). The accumulated degree-days for the last date of the current year (March 31) mentioned in the table are based on the weather forecast.
Site/Date 03/31 04/07 4/14 4/21 4/28
Biglerville, 2012 415 - - - -
Biglerville, 2011 138 179 245 338 454
Biglerville, 2010 194 334 412 486 562
Biglerville, 2009 157 210 242 305 439
Biglerville, 2008 137 178 255 355 472
Biglerville, 2007 213 249 259 290 394
Rock Spring, 2012 323 - - - -
Rock Spring, 2011 78 96 147 203 293
Rock Spring, 2010 141 277 342 408 463
Rock Spring, 2009 116 156 173 226 349
Rock Spring, 2008 61 88 146 240 352
Rock Spring, 2007 147 189 192 218 300