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Field studies were conducted from 1992 to 1996 to select the most effective sex pheromone blend for mating disruption of the obliquebanded leafroller, Choristoneura rosaceana (Harris), in tree fruit orchards in Washington. Dispensers loaded with a 2-component pheromone blend, ( Z )-11-tetradecen-1-yl (Z11-14:OAc) and ( E )-11-tetradecen-1-yl (E11-14:OAc), a 3-component blend that included the addition of ( Z )-11-tetradecenal (Z11-14:Ald), and a 4-component blend also including ( Z )-11-tetradecen-1-ol (Z11-14:OH) were compared within 0.1-ha orchard plots and 100-m2 field cages. The addition of Z11-14:Ald to the 2 acetate components with or without Z11-14:OH did not improve mating or disruption of communication. No disruption occurred in field cages treated with E11-14:OAc alone or an 88:12 (%) E:Z 11-14:OAc blend. Management of C. rosaceana with mating disruption was evaluated for 2 yr in three 16-ha apple orchards by using a 94:6% Z:E11-14:OAc blend. Orchards were treated with 1,000 polyethylene tube dispensers per hectare emitting ≈0.9 mg of pheromone per day. Populations were also monitored in 3 similar 8-ha orchards treated only with insecticides. Catches of male moths in traps baited with synthetic lures and virgin females were significantly lower (92–99%) in pheromone-treated than in untreated orchards. Larval population densities and fruit injury did not differ between treatments. No significant differences were found in larval population densities, trap catch, or fruit injury between the 2-ha center and the outer 14-ha areas of the pheromone-treated orchards. Significant increases in catch by lure-baited traps and fruit injury occurred in the pheromone-treated orchards from the 1st to 2nd yr of the study. The pheromone treatment saved ≈$250/ha in insecticide costs over 2 yr.

Our objectives were to predict pheromone-trap catches and oviposition of blackheaded fireworm, Rhopobota naevana (Hubner), on commercial cranberry farms in Wisconsin, Washington, Oregon, and British Columbia and to model oviposition in Wisconsin. Real time, expressed as days after male moths were caught in traps, predicted the day of 50% catch better than degree-days in both growing regions. Weibull functions were used to model the cumulative percentage of male moths caught and cumulative percentage of eggs laid over time in a Wisconsin cranberry farm not treated with insecticides and the percentage of catch of male moths on insecticide-treated farms in Wisconsin and the Pacific Coast growing region. Insecticide treatments made the patterns of flight activity less predictable. However, characteristics of flight activity common to all regions indicated oviposition may occur during a 4-wk period after first catch.

Phenology of blackheaded fireworm larvae, Rhopobota naevana (Hubner), was simulated with developmental rate-summation models. The relationship between temperature and median developmental rates of third instars and pupae were determined by using linear splines. Variation in developmental rates within a population was determined by using Weibull functions. Phenology of summer-generation larvae was simulated in multiple weekly cohorts starting from the estimated times eggs were laid. The model predicted within an average of 1 d (σ = 3.6 d) the date when 50% of the larvae in the field were past the second stadium. Development of larvae in the spring was predicted starting from the time of hatch of sampled eggs. The model included lower developmental rates and higher mortality before new leaves were available. When diet was included in the model, it predicted the date when 50% of the spring-generation larvae was past the second stadium within an average of 2.5 d. The models for the spring and summer generations were sensitive to the estimated dates of egg hatch and oviposition, respectively.

Egg hatch of blackheaded fireworm, Rhopobota naevana (H¨bner), was monitored in Wisconsin and British Columbia. In Wisconsin, hatch of overwintering eggs began during the last 2 wk of April, median hatch occurred during the first week of May, and hatch ended in late May. In British Columbia, hatch began in late March to early April, median hatch occurred in April, and hatch ended (except for one egg in both years that hatched in June) in late April in 1991 but extended into late May in 1992. Summer-generation eggs began hatching 2–7 d and completed hatch 6–15 d after oviposition in both regions. A linear spline model developed in Wisconsin predicted 50% hatch of overwintering eggs in Wisconsin to within ±5.5 d standard deviation. The model had extreme error in predicting hatch in British Columbia. A linear model predicted 50% hatch of summer-generation eggs in both Wisconsin and British Columbia to within ±1d standard deviation.

The first seasonal flight of male Sparganothis sulfureana was monitored with pheromone traps in a Wisconsin cranberry bed, and the dates of first catch and 50% catch were recorded. The number of days from first catch to 50% catch varied less than accumulated degree-days from first to 50% catch. A Weibull function was used to model cumulative percentage capture as a function of days after first catch. Predictions by the function were evaluated with data sets from locations in Wisconsin, Massachusetts, and New Jersey. The function predicted 50% catch within a mean of less than a day, and the error of the predictions had a standard deviation of 3.9 d in Wisconsin. The Wisconsin model tended to predict late in other states, thus alternative models are proposed.

Young blackheaded fireworm, Rhopobota naevana (Hubner), feed on old leaves or, when available, new leaves of cranberry, Vaccinium macrocarpon Aiton. In laboratory choice experiments, first-instar caterpillars preferred new leaves to old leaves regardless of temperature and photoperiod or generation of larvae. In no-choice tests, more larvae died before feeding (61.4%) when exploring dormant cuttings with only old leaves than did those exploring growing cuttings (11.8%). Larvae continued to reject old leaves and climb to the top of shoots even when deprived of food. Duration of the first stadium was 65% longer on overwintered leaves compared with young leaves. Survival of larvae in commercial cranberry marshes was 4.9 times greater after new shoot growth than survival of larvae hatched before new growth.

Survival of larvae of blackheaded fireworm, Rhopobota naevana (Hubner), was determined in two experiments where insects were submerged in water of different temperatures or dissolved oxygen content. Water temperature at high (8.2-13.1 ppm) dissolved oxygen did not affect survival significantly; 47% survived at 2°C and 41% at 10°C after 9 d. Dissolved oxygen affected survival significantly; only 7% survived in water oflow dissolved oxygen (5.1-7.1 ppm) at 10°C for 3 d compared with 91% at high dissolved oxygen (8.8-9.8 ppm). Flooding to control fireworm larvae was evaluated on three commercial cranberry marshes. A 25-50-h spring flood while vines were dormant resulted in a significant reduction of larvae. Data show that flooding may be useful to manage blackheaded fireworm.

The main study (Test 1) was conducted in an irrigated Kentucky bluegrass fairway in Lexington, Ky. The initial infestation level was about eight third-stage beetle grubs per ft . Thatch accumulation was negligible and temperature at the time of treatment (9 a.m., 31 Aug.) was 85°C, with sunny skies and almost no wind. The experimental design was a RCB with four replications. Individual plots were 6 by 9 ft with a 1-ft boundary between all plots. Granular materials were mixed with sand and hand shaken over the plots. Liquid formulations were mixed with water at the proper rates and applied with a low volume CO2 sprayer equipped with four Spraying System 730308 Tee Jet nozzles operated at 30 lb/in2. After all treatments were applied, the entire site was irrigated with about 1.5 in. of water using the golf course sprinkler system. The pH of the water used for mixing sprays and for irrigation was 6.2. Surviving grubs were sampled after 9 and 28 days by cutting a 1 by 7-ft strip lengthwise through each plot with a mechanical sod cutter, and examining the sod and underlying soil for grubs. Because the variances were proportional to the squares of the treatment means, a logarithmic transformation was used before ANOVA. The actual means for the grub counts are reported in the table. To confirm the relative effectiveness of Diazinon vs. Mocap, a second test (Test 2) was conducted in another, heavily infested fairway (ca. 18 grubs/ft2). Plots were 9 by 9 ft and were treated on 12 Sep. Methods of application, irrigation, sampling and data analysis were as described above. The plots were sampled 15 days after treatment (DAT).