Robert G. Hollingsworth

Limonene, a Citrus Extract, for Control of Mealybugs and Scale Insects

Abstract In a series of bioassays with mealybugs, aqueous solutions of 1% limonene were tested that used from 0.50 to 1.50% all purpose spray adjuvant (APSA)-80 as an emulsifier/surfactant. The two ingredients were added to water or to 0.1% Silwet L-77, an agricultural surfactant. Using 1% limonene, 0.75% APSA-80 and 0.1% Silwet L-77, a semitransparent mixture (primarily a microemulsion) was obtained that was safe for most plants and provided good control of mealybugs when sprayed or used in 1-min dips. Used at half strength, this mixture controlled ≥99% of whiteflies, whereas the full-strength mixture controlled from 69 to 100% of mealybugs and scales, including ≥93% control of root mealybugs. In side-by-side greenhouse tests, this mixture was superior to a 2% solution of insecticidal soap or a 2% solution of horticultural spray oil. Mortality of green scales on potted gardenia plants averaged 95, 89, and 88% on plants sprayed with limonene, insecticidal soap, or horticultural oil, respectively. In a related test, these same sprays killed 44.1, 22.7, or 12.5% of third and fourth instar clustering mealybugs, respectively. Limonene has promise as a safe, natural pesticide for insect pests on tolerant plants. Although 1% limonene solutions damaged certain species of ferns, gingers and delicate flowers, they caused no damage to ornamentals with thick, waxy leaves, such as palms, cycads, and orchids.

Scouting Methods for Detection of Thrips (Thysanoptera: Thripidae) on Dendrobium Orchids in Hawaii

Abstract Thrips are important pests of dendrobium orchid flowers in Hawaii primarily because of the risk that exported flowers found to be infested will be rejected by quarantine inspectors. Using nondestructive sampling, the population dynamics of thrips infesting dendrobium orchids was monitored at two farms on the Island of Hawaii over a period of 1 yr. Average thrips populations varied between 0 and 1.0 thrips per spray (flower spike). At both sites, adult thrips almost always outnumbered nymphs. The western flower thrips, Frankliniella occidentalis (Pergande), was the predominant species found. Using randomization tests, adult thrips were found to be randomly distributed on orchid sprays. The binomial probability distribution was used to graphically describe the accuracy of scouting results as a function of sample size and the proportion of thrips-infested flowers. Efficient methods for counting adult thrips included nondestructive field counts (direct observation), flower shakes, and extractions via Berlese funnels.

Ionizing Radiation for Quarantine Control of Opogona sacchari (Lepidoptera: Tineidae)

Abstract A discriminating irradiation dose of 150 gray (Gy) was used to determine the most tolerant immature stages of Opogona sacchari (Bojer) (Lepidoptera: Tineidae). Based on adult emergence, early and late pupae were determined to be the most tolerant stages, and they were significantly more tolerant than eggs, neonate larvae, and larvae that were 1, 2, or 3 wk old. Irradiation treatment of eggs, neonates, 1-wk-old larvae, 2-wk-old larvae, 3-wk-old larvae, early pupae, and late pupae at 150 Gy resulted in a 96, 96, 95, 73, 61, 8, and 9% reduction in adult emergence, respectively. Pupae were treated with irradiation doses between 60 and 400 Gy. Emergence to the adult stage was significantly reduced by irradiation, averaging 90% in experimental controls and 29% in the 400-Gy treatment. Egg production was also reduced by irradiation, although the average age of pupae at the time of irradiation had a larger effect on fecundity. In total, 2,527 pupae treated with 120 Gy eclosed and produced 47,221 eggs and three F1 larvae. In the 150-Gy treatment, 2,927 adults in total emerged from the 4,626 insects treated as pupae. These adults laid 62,878 eggs, none of which hatched. We conclude that a minimum dose of 150 Gy should be sufficient for sterilization of immature O. sacchari infesting export commodities.

Integrated Pest Management of Coffee Berry Borer in Hawaii and Puerto Rico: Current Status and Prospects

The coffee berry borer (CBB), Hypothenemus hampei, is the most significant insect pest of coffee worldwide. Since CBB was detected in Puerto Rico in 2007 and Hawaii in 2010, coffee growers from these islands are facing increased costs, reduced coffee quality, and increased pest management challenges. Here, we outline the CBB situation, and summarize the findings of growers, researchers, and extension professionals working with CBB in Hawaii. Recommendations for the Integrated Pest Management (IPM) program for CBB in Hawaiian Islands and Puerto Rico include: (1) establish a CBB monitoring program, (2) synchronize applications of insecticides with peak flight activity of CBB especially during the early coffee season, (3) conduct efficient strip-picking as soon as possible after harvest and perform pre-harvest sanitation picks in CBB hotspots if needed, (4) establish protocols to prevent the escape of CBB from processing areas and when transporting berries during harvest, and (5) stump prune by blocks. Progress achieved includes the introduction of the mycoinsecticide Beauveria bassiana to coffee plantations, the coordination of area-wide CBB surveys, the establishment and augmentation of native beetle predators, and an observed reduction of CBB populations and increased coffee quality where IPM programs were established. However, CBB remains a challenge for coffee growers due to regional variability in CBB pressures, high costs, and labor issues, including a lack of training and awareness of CBB management practices among growers.

Freezing as a Treatment to Prevent the Spread of Hypothenemus hampei (Coleoptera: Curculionidae), in Coffee

ABSTRACT Coffee berry borer, Hypothenemus hampei (Ferrari) is the most serious insect pest of coffee around the world. Although it is already present in most of the worlds major coffee growing regions, it is important to delay further spread and to prevent reintroductions that might include hyperparasites or improve the genetic base of existing populations. Green coffee is shipped around the world for custom blending and roasting and such shipments carry the risk of spreading H. hampei. We used heavily infested coffee berries as a surrogate for green coffee to test the freezing tolerance of H. hampei. After freezing, all life stages of H. hampei were dissected from coffee berries and mortality was assessed. Counting all life stages, >15,000 insects were measured in this study. A temperature of approximately -15°C (range, -13.9 to -15.5) for 48 h provided 100% control of all life stages. A logit regression model predicted ≤1 survivor in a million for treatments of -20°C for 5 d or -15°C for 6 d. A freezing treatment for green coffee might be more economical and acceptable compared with fumigation with methyl bromide, especially for small-scale and organic growers and millers in Hawaii who ship green coffee beans to other islands for custom roasting. Freezing treatments could also be used to kill H. hampei in coffee seeds before export with minimal effects on seed germination if coffee seeds are first dried to critical water content levels in accordance with published methods.

Sex attractant for the banana moth, Opogona sacchari Bojer (Lepidoptera: Tineidae): provisional identification and field evaluation.

BACKGROUND The banana moth, Opogona sacchari Bojer, is a polyphagous agricultural pest in many tropical areas of the world. The identification of an attractant for male O. sacchari could offer new methods for detection, study and control. RESULTS A compound extracted from female O. sacchari elicited responses from antennae of male moths. This compound was identified as a 2/3,(Z)13-octadecadienal by gas chromatography-mass spectrometry. An analog, 2/3,(Z)13-octadecadienol, was also detected in some extracts at roughly a 1:20 ratio (alcohol:aldehyde) but did not elicit responses from antennae of male moths. Electroantennograms of synthetic candidate dienals found the strongest responses from (Z, Z)-2,13-octadecadienal and (E, Z)-2,13-octadecadienal. In field trials, (E, Z)-2,13-octadecadienal attracted more male O. sacchari than (Z, Z)-2,13-octadecadienal. Attraction was not improved for either of these compounds when the corresponding stereoisomeric alcohol was added at ratios of 1:1, 1:10 or 1:100 (alcohol:aldehyde). Jackson sticky traps containing 250 microg lures of (E, Z)-2,13-octadecadienal caught as many males as did traps holding virgin females. CONCLUSION (E, Z)-2,13-octadecadienal has been identified as an attractant for O. sacchari males and can be used as a monitoring lure of populations of this moth.

Flight Activity and Field Infestation Relationships for Coffee Berry Borer in Commercial Coffee Plantations in Kona and Kau Districts, Hawaii

Abstract The coffee berry borer (CBB), Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae) is a recent invader to Hawaii.To date, limited information regarding the seasonal phenology of this pest on the islands limits the implementation of integrated control strategies. As part of a coffee farmer training program, we monitored CBB flight activity in 15 coffee plantations (Kona and Kau Districts) over 10 mo with methanol-ethanol (3:1 ratio) baited traps. Concurrently, we quantified CBB infestation and penetration rates inside developing coffee berries through the end of harvest. Approximately 1 million CBB were captured, with the highest activity (e.g., >500 CBB/trap/wk) in December through February, coinciding with end of main regional harvesting periods. Relatively high activity (>250 CBB/trap/wk) was also observed during berry development, in May and June (Kona) and June and July (Kau). Field infestation rates were higher overall in Kau (9.6 ± 1.1%) compared with coffee plantations in Kona (4.7 ± 0.4%). Linear regression investigated relationships between CBB trap data and berry infestation rates. Trap catch data generally correlated better with the proportion of shallow entries (AB position) compared with deeper penetrations (CD position) or total infestation. Pearson correlation coefficients based on different parameters (i.e., region, altitude, and berry phenology) revealed positive and mostly significant correlations between these variables (R values 0.410 to 0.837). Timing peak flight activity of CBB with insecticide applications will help coffee growers improve pest control.The ability of trap data to calculate reliable economic (action) thresholds for the CBB is discussed.

The Hawaii Protocol for Scientific Monitoring of Coffee Berry Borer: a Model for Coffee Agroecosystems Worldwide

Coffee berry borer (CBB) is the most devastating insect pest for coffee crops worldwide. We developed a scientific monitoring protocol that is aimed at capturing and quantifying the dynamics and impact of this invasive insect pest as well as the development of its host plant across a heterogeneous landscape. The cornerstone of this comprehensive monitoring system is timely georeferenced data collection on CBB movement, coffee berry infestation, mortality by the fungus Beauveria bassiana, and coffee plant phenology via a mobile electronic data recording application. This electronic data collection system allows field records to be georeferenced through built-in global positioning systems, and is backed by a network of weather stations and records of farm management practices. Comprehensive monitoring of CBB and host plant dynamics is an essential part of an area-wide project in Hawaii to aggregate landscape-level data for research to improve management practices. Coffee agroecosystems in other parts of the world that experience highly variable environmental and socioeconomic factors will also benefit from implementing this protocol, in that it will drive the development of customized integrated pest management (IPM) to manage CBB populations.