Late Summer Considerations in Controlling Fruit Insect Pests
Posted: July 30, 2012
Brown Marmorated Stink Bug
We are continuously finding all possible instars of brown marmorated stink bug (BMSB) on various wild plants in vegetation and woods surrounding orchards but not too many in orchards themselves. This past week we observed the first significant numbers of BMSB in soybean fields, but only where soybean plants already have developed pods. Fortunately, so far (July 29), our BMSB monitoring activities, which include visual surveying of orchards and border areas around orchards did not detect any rapid movement of BMSB populations from surrounding vegetation into orchards. Although the visual monitoring still remains the best monitoring technique, finally the currently available traps and lures utilizing another stink bug (Plautia stali) aggregation pheromone started to systematically capture BMSB nymphs and some adults. The movement of summer adults from outside hosts into orchards (or other crops) and associated deposition of new eggs could become a significant source of new BMSB infestation in orchards. While the nymphal feeding can be reduced by effective and well-timed insecticide treatments, the feeding by continuously wandering BMSB adults is very difficult to manage. While at this moment the BMSB pressure from within orchard resident BMSB populations is mostly non-existent, the BMSB adults established outside of the orchards will represent a continuous challenge for the rest of this season. With all other “traditional pests” also present in the orchard, it is again becoming very important that the choice of insecticides directed against other pests should also affect (preferably control) the portion of BMSB population present in orchards at the time of application. With about 10 more weeks of BMSB activity to go (until mid-October), it is extremely important that growers plan ahead with the choice of products utilized against BMSB, and preserve the most effective options, especially with the shortest Pre-Harvest Intervals (PHI), for applications when the pressure from this pest will increase in the later part of this season.
During the last month, two additional active ingredients: dinotefuran (neonicotinoid) and bifenthrin (pyrethroid) were registered in Pennsylvania under EPA Section 18 Emergency Exemptions to help manage BMSB populations. Please see the article on these new registrations for more information.
Leafrollers and Oriental Fruit Moth—Late Season Generation Flights Earlier than Anticipated
Although during this season the egg hatch models based on degree-day accumulation appear to be running ahead of observed moths’ activities in orchards (mostly due to the unusual weather pattern in the spring), the flight of the second generation of codling moth (CM) and the third generation of Oriental fruit moth (OFM) is well underway in orchards located in south-central Pennsylvania. Also, our two leafroller species, tufted apple bud moth (TABM) and obliquebanded leafroller (OBLR), started their second generation flight. It is very important to closely monitor each pest population, especially in orchards with a previous history of CM, OFM, TABM or OBLR problems. Delegate® at the rate of 4.5 oz or above, Altacor® at the rate of 3.0 oz or above and Belt® at the rate of 5.0 oz or above are highly active against CM, OFM, TABM and OBLR. These recommended products are excellent and highly effective insecticides against targeted pests, but unfortunately they will not control BMSB, and other products may be needed to protect fruit against this troublesome pest. If growers know that certain insecticides do not provide effective CM control (i.e., due to insecticide resistance), they should consider the use of different compounds with CM activity, not previously used in the problem block, i.e., Avaunt™ at 6 oz/acre (14 day PHI), Calypso™ at 5-6 oz/acre (30 day PHI), Intrepid™ at 16 oz/acre (14 day PHI)), Rimon® at 20-30 fl oz/acre (14 day PHI), Cyd-X at 2-4 oz/acre or Carpovirusine at 6.8-13.5 oz/acre.
Due to existing pressure from BMSB, the incorporation of effective products against stink bugs during late season applications may be warranted for many orchards, especially those located in the southern part of Pennsylvania. Although not every orchard will experience the same pressure from BMSB, we anticipate that most blocks located next to woods or other BMSB sources (e.g., some agronomic crops) would require special protection against migrating BMSB adults and developing nymphs. Products with active ingredient such as methomyl (i.e., Lannate SP and Lannate LV; IRAC Group 1A) should not only control BMSB but also help control leafrollers such as TABM and OBLR. Neonicotinoid insecticides (IRAC Group 4A) such as Assail™ 30SG or Belay ® will not only help control various instars of BMSB but also should protect against CM and OFM neonates.
Pyrethroid insecticides, while somehow only effective against BMSB, should also provide some control of OFM larvae. However, this class of insecticides did not perform well in our research trials testing for control of CM larvae late during the season. In this group of insecticide chemistries (IRAC Group 3A), Danitol ® and products containing bifenthrin were the most effective against BMSB.
Seasonal Activity of Fruit Pests
2012 season weekly captures of adult moths in pheromone traps located at Penn State FREC, Biglerville, PA (Adams County):
|Key to acronyms: RBLR - redbanded leafroller; STLM - spotted tentiform leafminer; OFM - Oriental fruit moth; CM – codling moth; TABM – tufted apple bud moth; OBLR- obliquebanded lefroller; DWB – dogwood borer; PTB – peach tree borer; LPTB – lesser peach tree borer.|
Accumulated degree-days base 43° F from Jan 01 for each reported year (courtesy of SkyBit, Inc.).
|Rock Spring, 2012||2001||2249||2435||2656||2872|
|Rock Spring, 2011||1719||1931||2116||2353||2582|
|Rock Spring, 2010||1878||2096||2284||2510||2723|
|Rock Spring, 2009||1569||1725||1862||2028||2219|
|Rock Spring, 2008||1553||1710||1916||2136||2327|