Plum Curculio (PC) adults have been late to arrive in Highland with only early scarring to fruit observed by the 23rd of May. Up to this point in time night temperatures have been below 50F. PC activity is highly dependent upon temperatures, particularly at night when adults are most active. PC typically do not feed or oviposit when nighttime temperatures are below 50 deg F. In cooler seasons such as this, PC may continue to delay with extended oviposition for 4-6 weeks. As the adults begin to move in cooler weather, they often crawl instead of fly or fly short distances, damaging fruit along the edge first, moving among trees into the orchard center from the edge in commercial orchards. We presently have 65 accumulated degree days (base 50°F) from petal fall (May 19th) through 5/24/2014. Control measures are only needed until 308 degree days have accumulated since petal fall. Based on limited and unreliable weather patterns, the forecast date for the 308DD is approximately June 14th. Insecticide residual will need to be effective until PC have completed emergence. NEWA Model for PC at the Highland Station can be accessed here.
Frequent short interval rains will remove surface contact insecticide residual. Incidence of observed PC damage is highly variable among different orchards. PC damage often occurs in the same locations in orchards year after year, regardless of treatment levels with the potential for damage in any particular orchard fairly predictable from past observations.
This season given the delay in emergence from cool temperatures, a post-petal fall spray for control of PC is necessary, even in low-pressure orchards. In high-pressure orchards, additional sprays along the perimeter of the orchards should be applied until the oviposition model predicts that control is no longer necessary.
Insecticides effective against the PC include Avaunt 30WDG (indoxacarb), the neonicotinoids; Actara 25WDG (thiamethoxam), Calypso 4F (thiacloprid), the OP Imidan 70WP, WSP (Phosmet), carbamate; Sevin (carbaryl), and pyrethroids Danitol 2.4EC (fenpropathrin), Asana XL (esfenvalerate), Baythroid XL 1E, 2EC (beta-cyfluthrin), Lambda-Cy 1CS (lambda-cyhalothrin), Warrior 1CS (lambda-cyhalothrin), Proaxis 0.5CS, and pre-mix formulations Endigo ZC (lambda-cyhalothrin / thiamethoxam), Leverage 360 (imidacloprid / beta-cyfluthrin), Gladiator (zeta-cypermethrin / avermectin), Voliam Express (lambda-cyhalothrin / thiamethoxam), Voliam Flexi (chlorantraniliprol / thiamethoxam).
This will be the last year for use of Calypso 4F, one of the better OP replacement materials for PC management.
The pyrethroids and phosmet have broad spectrum activity to include PC, EAS, lepidopteran larva (OFM, CM, Lesser appleworm (LAW) and Obliquebanded leafroller (OBLR). They have no activity against rosy apple aphid (RAA) in curled foliage.
Calypso 4F has activity against PC, EAS, RAA, leafhopper and leafminer, internal lepidopteran (OFM, LAW and CM) but only moderate to low activity against the OBLR.
The pre-mix ingredients:
Avermectin must be used with a penetrant to effectively manage mite.
Chlorantraniliprol, the active in Altacor, is excellent against the range of lepidopteran larva with limited spectrum.
Thiomethoxam with similar spectrum to Calypso, however, it has no efficacy against internal lepidopteran larva. Use exclusively at 1C will put you at risk against CM larva.
Oriental Fruit Moths are still flying and usually about 50-60% of OFM eggs from the first generation have hatched. A second spray should be applied at about 10-14 days after petal fall. This second spray against the first generation of OFM is particularly important in high-pressure orchards (past history of OFM fruit damage or high pheromone traps catches, (>10/ trap/ week) to control the remainder of hatching larvae. If this spray is applied at the normal time of a first cover spray (10-14 days after petal fall) it will also control early hatching CM larvae from the first flight of adults. Plum curculio is still active after PF in this cool, rainy season.
Codling Moth eggs are being laid this week. This begins at about 50 DD as we are at 54 DD in Highland, NY. The first eggs hatch after about 220 DD, which is predicted to occur on the 31st of May. Insecticides that need to be present before egg laying (Rimon) at about 50-75 DD, should be applied at the first available application window. Apply insecticides that target early egg laying period at 100-200 DD, over the next week using the 31st of May as the target date.