New Tools for Mechanical Thinning of Apricot Fruitlets

In this study, the thinner machine with yellow rod equipment was tested in relation to tree branch length and orientation in April 2019, in a narrow-canopied apricot orchard of Emilia Romagna Region, Italy. The trees were mechanically thinned with manual finishing, and comparative tests were carried out simultaneously with the ordinary hand thinning (control). Three groups of two plants were identified as replication for a total of six plants per row. Three rows were checked, considering field uniformity average. The branches were grouped into four classes according to their length: <30 cm, 30–60 cm, 60–90 cm and >90 cm. Branch inclination on the plant, radial or longitudinal with respect to the row, was evaluated. Fruit number before the thinning, after the first and the second machine intervention, after three days of the mechanical thinning and after the hand finishing was recorded. This experience showed satisfactory results in terms of thinning efficiency and reduced damage to both fruits and branches, as a function of the class length and insertion point in the main branch of the plant. Thinning efficiency was always kept above 37% of the left load after hand finishing, and on average between the treatments close to 44%. Fruit damages always remained below the economic thresholds to marketable production or to the plant.

Development of Economic Thresholds Toward Bollworm (Lepidoptera: Noctuidae), Management in Bt Cotton, and Assessment of the Benefits From Treating Bt Cotton With Insecticide

Widespread field-evolved resistance of bollworm [Helicoverpa zea (Boddie)] to Cry1 and Cry2 Bt proteins has threatened the utility of Bt cotton for managing bollworm. Consequently, foliar insecticide applications have been widely adopted to provide necessary additional control. Field experiments were conducted across the Mid-South and in Texas to devise economic thresholds for foliar insecticide applications targeting bollworm in cotton. Bt cotton technologies including TwinLink (TL; Cry1Ab+Cry2Ae), TwinLink Plus (TLP; Cry1Ab+Cry2Ae+Vip3Aa), Bollgard II (BG2; Cry1Ac+Cry2Ab), Bollgard 3 (BG3; Cry1Ac+Cry2Ab+Vip3Aa), WideStrike (WS; Cry1Ac+Cry1F), WideStrike 3 (WS3; Cry1Ac+Cry1F+Vip3Aa), and a non-Bt (NBT) variety were evaluated. Gain threshold, economic injury level, and economic thresholds were determined. A 6% fruiting form injury threshold was selected and compared with preventive treatments utilizing chlorantraniliprole. Additionally, the differences in yield from spraying bollworms was compared among Bt cotton technologies. The 6% fruiting form injury threshold resulted in a 25 and 75% reduction in insecticide applications relative to preventive sprays for WS and BG2, respectively. All Bt technologies tested in the current study exhibited a positive increase in yield from insecticide application. The frequency of yield increase from spraying WS was comparable to that of NBT. Significant yield increases due to insecticide application occurred less frequently in triple-gene Bt cotton. However, their frequencies were close to the dual-gene Bt cotton, except for WS. The results of our study suggest that 6% fruiting form injury is a viable threshold, and incorporating a vetted economic threshold into an Integrated Pest Management program targeting bollworm should improve the sustainability of cotton production.

Linking Federal Forest Restoration with Wood Utilization: Modeling Biomass Prices and Analyzing Forest Restoration Costs in the Northern Sierra Nevada

Over half of California’s forestland is managed by the US Forest Service, and the agency has identified a need to scale up forest restoration treatments in the state to one million acres per year by 2025. However, the high costs of mechanical fuel reduction and lack of markets for biomass pose significant barriers to accomplishing this target. The objectives of this case study were: (1) to identify costs of forest restoration treatments on federally-managed land in the Northern Sierra under a variety of harvesting scenarios and haul distances to biomass facilities, and (2) to understand what market prices for biomass must be offered to support such efforts. We modeled silvicultural prescription and harvesting options, machine productivity and costs, and transportation costs to assess economic thresholds. Biomass harvest, chip, and haul costs ranged from $55/bone dry ton to $118/bone dry ton, depending on the harvesting system scenario and distance from the biomass disposal site. Results suggest that the cost of forest restoration far exceeds current market prices for biomass, and additional investment is needed to adequately pay for federal forest restoration in California. Additional takeaways include that biomass outlets closer to supply sources can reduce both haul costs and production costs, and local wood utilization campuses can play a key role in supporting forest restoration.

Phytosanitary state of sugar beet agrocenosis in 2019 and forecast of the number of phytophages in the current year

Purpose. To generalize and analyze the data provided by state phytosanitary inspections of the Department of Phytosanitary Safety of the State Veterinary Service of Ukraine on the dynamics of development of the main pests in sugar beet stands in Ukraine in 2019 and to forecast their appearance and possible damage in the current year. Methods. Field, accounting, analytical. Results. In 2020, sugar beet crops may be damaged by beetroot weevil, grey beetroot weevil, beet stalk borer, beet flea, beet leaf miner, beetroot aphids and other pests. According to the results of autumn field monitoring, 57% of beet areas was colonized by beetroot beetle with an average number per 1 m2 of 0.5–1.0 (beetles, pupae) with the maximum number of 2–9 in Volyn, Kyiv, Poltava, Cherkasy, Chernihiv, Zhytomyr, Sumy regions. During the autumn excavations, the beetles in the population were 75%, pupae 20% and larvae 5%. In respect to grey beetroot weevil, it made the greatest damage to sugar beet crops in Kyiv, Poltava, Kharkiv, Sumy, Volyn, Kirovohrad, Khmelnytsk, and other regions, where it colonized 24–100% of stands with an average number of 0.1–0.6 with a maximum of 0.6–1.0. It damaged, on average, 2–6% of stands with the maximum of 7–12%. Autumn monitoring of the pest found a significant number of the pest in all beetroot regions with an average number of 0.5–0.7 with the maximum of 1.0–4.0. In addition, autumn monitoring revealed a significant number of beet stalk borer (average 0.1–0.7, maximum 0.7–1.0 specimens) in farms of Poltava and Cherkasy regions. Beet tortoise beetles were detected on 10–100% of the monitored area with an average number of 0.1–0.4, which is lower than in long-term observations. In the majority of areas, goosefoot tortoise beetles dominated (33–100%). On average, the ratio was 54% of goosefoot and 46% of beet root tortoise beetles. The wintering stock of beet beetle was slightly lower than in the last year and amounted to an average of 14–54, with the maximum in Vinnytsia, Rivne, Khmelnytskyi regions (76–100). Autumn inspections of host plants (red bilberry, snowball tree, jasmine) revealed 12–36, maximum 150 wintering eggs of leaf aphids per 1 meter of a branch. The wintering stock of beet leaf miner was 0.8–1.8, somewhere 2.9 (in Ternopil, Vinnytsia Khmelnytsk regions), which is at the level of the last year’s numbers. Conclusions. The wintering stock of harmful sugar beet insects exceeds the generally accepted economic thresholds for harmfulness. The timely prognosis of the development and reproduction of sugar beet pests and the application of a complex of organizational, economic, biological and chemical measures to control their numbers will create conditions for the preservation of root harvest, improving root quality and reduce unreasonable pollution of the environment with chemicals.

Economic Injury Levels for Bt-resistant Helicoverpa zea (Lepidoptera: Noctuidae) in Cotton

Thresholds for Helicoverpa zea (Boddie) in cotton Gossypium hirsutum L. have been understudied since the widespread adoption of Bt cotton in the United States. Our study was possible due to the widespread presence of H. zea populations with Cry-toxin resistance. We initiated progressive spray timing experiments using three Bt cotton brands (Deltapine, Stoneville, and Phytogen) widely planted across the U.S. Cotton Belt expressing pyramided toxins in the Cry1A, Cry2, and Vip3Aa19 families. We timed foliar insecticide treatments based on week of bloom to manipulate H. zea populations in tandem with crop development during 2017 and 2018. We hypothesized that non-Bt cotton, cotton expressing Cry toxins alone, and cotton expressing Cry and Vip3Aa19 toxins would respond differently to H. zea feeding. We calculated economic injury levels to support the development of economic thresholds from significant responses. Pressure from H. zea was high during both years. Squares and bolls damaged by H. zea had the strongest negative yield associations, followed by larval number on squares. There were fewer yield associations with larval number on bolls and with number of H. zea eggs on the plant. Larval population levels were very low on varieties expressing Vip3Aa19. Yield response varied across experiments and varieties, suggesting that it is difficult to pinpoint precise economic injury levels. Nonetheless, our results generally suggest that current economic thresholds for H. zea in cotton are too high. Economic injury levels from comparisons between non-Bt varieties and those expressing only Cry toxins could inform future thresholds once H. zea evolves resistance to Vip3Aa19.

Volunteer Canola (Brassica napus L.) interference with soybean [Glycine max (L.) Merr.]: Management thresholds, plant development, and seed return.

Canola (Brassica napus L.) and soybean [Glycine max (L.) Merr.] are currently two of the three most common crops grown in Manitoba which comprises the eastern regions of the Canadian Prairies. Volunteer B. napus is a prominent weed in soybean in Manitoba and glyphosate-resistant (GR) volunteer B. napus often is the only weed remaining after in-crop weed control with glyphosate in soybean. Additive-series field experiments were established at three locations in Manitoba in 2012 and 2013 to study volunteer B. napus interference with soybean and develop action and economic thresholds for this weed. Soybean were planted in narrow- (25-cm) or wide- (75-cm) row spacing and glyphosate-resistant B. napus seed was broadcast at densities of 0, 10, 20, 40, 80, 160, 320 and 640 seeds m-2 at the time of soybean planting. Development of soybean and volunteer B. napus were determined throughout the growing season and seed yield of both species was determined at their respective physiological maturity. Volunteer B. napus is highly competitive with soybean as action (< 9 plants m-2) and economic (< 5 plants m-2) thresholds were low. At these action thresholds, volunteer B. napus seed return to the weed seedbank was on average 14,400 seeds m-2 and 10,400 seeds m-2 in narrow and wide row soybean, respectively.

Perception and Use of Economic Thresholds Among Farmers and Agricultural Professionals: A Case Study on Soybean Aphid in Minnesota

Economic thresholds (ETs) are a foundational principle of integrated pest management but are not always widely accepted by farmers and agricultural professionals. This article reports on a survey of Minnesota farmer and agricultural professional perceptions of the ET for soybean aphid, Aphis glycines Matsumura (Hempitera: Aphididae). We discuss insights for Extension programs on how to frame the importance of thresholds and teach stakeholders to use them effectively. Key takeaways include farmers and agricultural professionals often worry about combined effects of insect, disease, and physiological pressures, whereas effects of interactions with these other stressors are seldom discussed in educational outreach. Across groups, there is a fundamental misunderstanding about the difference between ETs and economic injury level. Many survey participants reported believing in the ET but lacked the time and capacity to fully implement it. Sales agronomists and farmers were the least likely groups to trust the university-determined soybean aphid ET, whereas commercial pesticide applicators and independent consultants were the most likely groups to trust it. Based on these results, we recommend adapting communication about ETs based on the target audience to address common misconceptions and barriers to ET use that are unique to each group.