As we move toward petal fall, pest management decision-making should take into account problems that occurred last season, the endemic pests residing in the orchard, those that caused fruit injury causing culls at packout, as well as the developing insect complex flying into the orchard over the next few days. Mid-Hudson Valley apple are in full bloom today (May 14th ) with warm temperature and scattered showers predicted for the remainder of the week. Scab and fire blight will likely precede insect pest management applications. Our scouting observations have shown little in the way of larva feeding on flowers or foliage, with a few rosy apple aphids in untreated and treated trees in Highland’s Hudson Valley Lab.
The insect to which we can attribute the highest losses in apple during the petal fall period is the Plum Curculio (PC), a native of North America and major pest of pome and stone fruits in the United States. Most commercial orchards are free of endemic PC populations as the adult moves in from hedgerows and woodlands to damage fruit
. PC overwinter as adults in ground litter or the soil and become active in the spring following several days of either a mean temperature above 60°F or maximum temperatures above 75°F. This is the weather we are seeing and forecasted for this week. However, if we see a temperature drop and conditions become unfavorable, the adults may return to hibernation sites. The emergence period for PC can last for several weeks, however, we can see 40-60% of the total emergence occurring on a single day with very high egg laying damage levels over a 24 hour period. With the loss of Guthion and the use of Lorsban at PF, we are finding fewer broad spectrum insecticides that manage the pest complex at petal fall. As there are numerous and effective materials available to manage PC, the OP replacement insecticide that provides low bee toxicity, excellent residual control of PC and the internal worm complex (PC, OFM, LAW), Rosy Apple Aphid (RAA), Green Apple Aphid (GAA) and White Apple Leafhopper control is the product Calypso 4F employed at moderate to high labeled rates (4-8 oz./A) depending on pest pressure. The OP Imidan70WS, pyrethroids and pyrethroid premix groups, Actara 25WDG at 4.5-5.5 oz./A, Avuant 30WDG at 5-6 oz./A will manage PC with varying degrees of activity against the pest spectrum. If you are relying on the repellency of the barrier film Surround (Kaolin Clay) instead of PC mortality through the use of conventional insecticides, coverage will need to be maintained until curculio egglaying declines, predicted to be the last week in June.
Control of the larva and pupal form of PC can be achieved using entomophagous nematode introductions with information available in PowerPoint of the on-going nematode research.
European Apple Sawfly (EAS): are primitive hymenopterous insects, related to bees, wasps, and ants having a single generation per year in NY. An introduced pest that was first noted in North America infesting Long Island crabapples in 1939. The pest is especially troublesome in the apple-growing regions of the Hudson Valley of New York with increasing levels of infestation occurring in more northerly regions of the state. The larvae feed on apple with a preference for early or long-blooming, heavy-set varieties. Years in which there is a very late bloom typically have very few EAS present to cause damage to early and mid-pollinating varieties with small amounts of damage noted to late harvested fruit. Timely controls for PC at PF will eliminate the need for EAS management in conventionally grown fruit. However, Surround WP used for organic PC management will only have marginal control of EAS. Late applications or a delay in PC management during cool years of prolonged bloom, will allow EAS larva to hatch and begin feeding, giving rise to apple injury.
The lepidopteran complex:
Our scouting report has shown potentially high numbers of Red Banded Leafroller (RBLR), Oriental Fruit Moth and increasing Lesser Apple Worm (LAW) adult populations that often give rise to larva that feed on flowers and developing fruit. As RBLR has been flying since the 14th of April, we have seen peak trap catch and the approximate start of egg hatch occurred on Monday, May 5th and will continue on through bloom. Although larva have yet to be observed in untreated trees in Highland, scouting should include sampling and observations for RBLR in flowering clusters. Since we haven’t seen the larva of green fruit worm (GFW) or Obliquebanded Leafroller (OBLR) during bloom in untreated trees, its likely high overwintering mortality and cool spring suppression of these insects have reduced the presence of populations to reduce the need for management of these pests? The warming trend this week should prove this either way. If they do become an issue at bloom, foliar and blossom feeding ‘worm’ can be held in check using Bt formulations. The Bt products such as Biobit, Dipel, Javelin, and MVP (IRAC 11 B2) also have a low impact on beneficial mite and are very effective against overwintering obliquebanded leafroller (OBLR) and the green fruit worm (GFW) complex. The Bt products can be used through bloom as needed and their use should be optimized employing multiple applications at 5-7 day intervals at the low-labeled rate.
• Intrepid (methoxyfen-ozide) (IRAC 18A) another reduced risk insecticide very effective against the larva, acts as an insect growth regulator to imitate the natural insect molting hormone and works by initiating the molting process. Activity of the insecticide is primarily through larval ingestion of foliage, excellent coverage is necessary for effective control. Intrepid is quite safe to birds, fish, and most beneficial insects and can be applied from pink through petal fall. It is registered on pome and stone fruits for control of oriental fruit moth, lesser apple worm, spotted tentiform leafminer and leafroller, with suppression of codling moth at the highest labeled rate. REI = 4-hours; PHI = 14 days (pome fruits), 7 days (nectarine, peach and plum).
• Proclaim (Emamectin Benzoate) is registered on pome fruit for the control of leafroller, spotted tentiform leafminer and suppression of codling moth, oriental fruit moth, lesser apple worm and spider mite in apple and pear psylla in pear. It interferes with neurotransmission in insects resulting in the loss of cell function and nerve impulse. Proclaim, when used with a penetrant, has translaminar activity through ingestion and limited contact activity. Proclaim 5SG rate is 3.2 to 4.8 oz. per acre and seasonal maximum of 14.4 oz per acre. Begin application at the onset of hatch to control early stage larvae. Apply using a minimum of 40 gal. of water per acre with a horticultural spray oil or a nonionic penetrating surfactant. Do not use a sticker or any other pesticide or product containing a sticker component in its formulation as stickers can drastically reduce pest control. REI = 48-hours; PHI = 14-days.
Oriental Fruit Moth (OFM): Flight began on April 28 with 1st generation egg hatch and treatment for >50% hatch beginning May 24th. To date we have not captured Codling Moth (CM) adult males. The 1st generation sustained trap catch biofix date for CM has a historical mean date of Friday, May 16th. ‘In the old days’ insecticides targeting plum curculio would prevent codling moth damage. However, with the future loss of Calypso at the end of 2014, loss of Lorsban use at PF, which would control adult CM, and loss of Guthion and other contact insecticides efficacious against CM, we are left with fewer broad spectrum insecticides that manage both PC and CM. Since larva emergence typically occurs during the 2nd cover window we don’t need to address this insect yet, however, If you use Actara for PC control, lepidopteran will be an issue. Using only Actara at 2nd will leave you open for lesser apple worm and codling moth.
The Tarnished Plant Bug (TPB): is a predominately a pre-bloom pest of apple, a true bug in the order Hemiptera, with piercing-sucking mouthparts such as is found in aphids and leafhoppers. The adult TPB has a color appearance ranging from dull brown to black. The rear half of the forewings are membranous and are bent downward with a distinct yellow triangle behind the head. The adult bugs hibernate under leaf liter, clover, alfalfa, mullein and protected places of stonewalls and tree bark. Orchards with weed host density are more prone to damage. Control of weed hosts, such as common mustard weed, has been shown to reduce fruit injury. They become active at relatively low temperatures (> 46oF) with feeding becoming pronounced at temperature at or above 70oF, between tight cluster through the post bloom period of apple. The pyrethroids (Asana, Ambush, Baythroid, Danitol, Pounce, Warrior ) are most effective, followed by the neonicotinoid group including Actara, Calypso Assail and Avaunt, which are moderately effective. Pyrethroids and neonicotinoids will also impact many of the insect pests damaging to fruit such as RAA, STLM and early immigrating PC.
Mullein Plant Bug (MPB): and apple brown bug (ABB) are occasional pests that move into trees during the pre-bloom period, feeding on fruit shortly after fruit set. In blocks where historical injury has been observed, scouting for this insect in Red Delicious, Golden Delicious, Northern Spy, and Spartan with McIntosh seldom suffering damage. The expected 50% egg hatch date is Wednesday, May 14, about 5 days before rough estimate of Red Delicious petal fall date with 90% egg hatch date expected by May 19th. MPB and ABB are pests only during the period from bloom through about the time fruit are 0.5 inches in diameter. After that, they are beneficial, preying on European red mite, aphids, psylla, and other insects. Petal fall insecticide applications will kill most of the nymphs present, with some of the damage occurring by then. Petal fall sprays should be applied as soon as possible after blossoms are off. Assail, Actara, and pyrethroids are quite effective against the insect.
San Jose Scale (SJS): If pre-bloom applications of 1-3% oil, Lorsban alone or with oil, Esteem or Centaur were applied effectively to blocks with know SJS populations then you can relax until nymph emergence during 3rd cover, predicted to emerge on the 18th of June this season. Scouting for nymphs in mid-June will determine if your pre-bloom applications were effective. However, you will need to consider the use of Movento 240SC at 6-9 oz./A plus a non-ionic penetrant such as 0.25% to 1% agricultural oil to address the San Jose Scale fruit injury at pack out last year if pre-bloom applications were omitted this season. The active ingredient in Movento, spirotetramat, is taken into the foliage, systemically moving through plant tissue to stems, roots, and leaves to be fed upon by emerging SJS nymphs during emergence and feeding. Our research has found the single application of 9 oz./A at PF or two applications at 6 oz./A at PF and 2C to effectively control the 1st generation of the insect.