Abstract

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae Kuwana) is an invasive pest that primarily infests crapemyrtles (Lagerstroemia spp.), along with a few other economically important plants in the U.S. Current management practices predominantly rely on neonicotinoid insecticides, which are structurally similar to nicotine and act as agonists at nicotinic acetylcholine receptors (nAChRs), disrupting insect nervous systems. However, the specific impact of these insecticides on CMBS herbivory performance remains unclear. This study combines pectinolytic enzyme detection and electrical penetration graph (EPG) techniques to investigate nicotine’s impact on CMBS salivation and ingestion. CMBS feeding assays were conducted on agarose plates containing various concentrations of pectin and nicotine. The enzyme detection experiments revealed CMBS salivation involves pectinesterase and polygalacturonase secretion, unaffected by nicotine. Consistent with these findings, EPG analysis confirmed salivation (waveform E1) occurred in nicotine-containing agarose. Unexpectedly, phloem sap ingestion (waveform E2) was absent when nicotine was added to the agarose, indicating selective inhibition of CMBS ingestion. These findings suggest nAChRs specifically regulate sap ingestion in CMBS, but not salivation and other feeding behaviors. These insights into nicotine and neonicotinoid insecticide action on CMBS could inform precision insecticide application in IPM programs, potentially enhancing control efficacy while reducing environmental impact.

Species used in this study: Crapemyrtle bark scale (Acanthococcus lagerstroemiae Kuwana).

Chemicals used in this study: Agarose (Bio-Rad Laboratories), pectin (MP Biomedicals), nicotine (Sigma-Aldrich), sucrose (Domino Foods Inc.), glutamine (Thermo Fisher Scientific), ruthenium red (Enzo Life Sciences Inc.).

Abstract

Cold hardy hazelnut [Corylus (L.) spp.], an emerging crop in the Upper Midwest, has been reported to exhibit symptoms aligned with Mouse Ear Disorder (MED) when cultivated using soilless substrates in containers. To test these claims, we questioned if supplemental nickel could correct symptomatic growth. Our objectives were to 1) characterize purported symptoms of non-treated American hazelnut C. americana (Walter) and hybrid hazelnut plants C. americana × C. avellana (L.) and 2) determine if symptoms are corrected by supplementing nickel. Seedlings of both taxa were treated with either (1) a non-treated control (H₂O spray) or foliar sprays of (2) Nickel Plus® (169 mg·L⁻¹ Ni), (3) NiCl₂ (169 mg·L⁻¹ Ni), (4) urea (150 mg·L⁻¹ N), and (5) combined NiCl₂ (169 mg·L⁻¹ Ni) and urea (150 mg·L⁻¹ N). Forty-five days post-treatment, plants were evaluated using a rating scale, leaf characterization metrics (greenness, count, surface area, dry mass, and specific area), and metrics characterizing stem traits (elongation and dry mass). Shoot elongation was the only response that differed between taxa and was influenced by treatments: NiCl₂ increased shoot elongation in American hazelnuts, whereas hybrids did not differ across treatments. These data suggest hazelnuts are susceptible to MED, with all nickel treatments mitigating symptoms.

Species used in this study: American hazelnut, Corylus americana (Walter); Interspecific hybrid hazelnut, C. americana (Walter) × C. avellana (L.).

Chemicals used in this study: NiCl₂; Nickel Plus®; urea.

Abstract

Exponential population growth pressures the agriculture industry to provide fresh foods to both rural and urban areas. GREENBOX technology, based on Controlled Environment Agriculture (CEA) principles, addresses this challenge by optimizing conditions for leafy green crops. It integrates into urban infrastructure to mitigate the effects of urbanization on fresh food availability. GREENBOX controls environmental factors like temperature, humidity, light, and nutrient delivery to enhance crop growth. Given that artificial lighting is a major energy consumer in CEA, this study explored different photoperiods to improve energy efficiency. Lactuca sativa ‘Rex Butterhead’ lettuce was grown under three photoperiods: 16-hour light/8-hour dark (control), 14-hour light/10-hour dark, and 12-hour light/12-hour dark. Biomass parameters, including fresh and dry weight, leaf area, leaf count, and chlorophyll concentration, were measured. While all treatments produced viable crops above the expected harvest weight, the 16-hour photoperiod caused statistically significant (p < 0.001) differences in fresh weight, dry weight, leaf count, Specific Leaf Area (SLA), and Leaf Area Index (LAI) compared to the shorter photoperiods. No significant differences were found between the 12-hour and 14-hour treatments. These results suggest that photoperiod adjustments could enhance the efficiency and productivity of GREENBOX units for urban agriculture.

Species used in this study: Rex ‘Butterhead’ lettuce, Latuca sativa L.

Abstract

Cutting propagation provides uniform plants that retain the original characteristics of the donor. This method requires forming adventitious roots. Our previous studies indicate that semi-lignified stem cuttings of American chestnut [Castanea dentata (Marshall) Borkh.] and yellow camellia (Camellia nitidissima Chi.) exhibit low levels of the rooting-promoting hormone indole-3-acetic acid and high levels of other hormones that inhibit rooting induction and development. Additionally, their hormone distribution between leaves and stems differs from that of easy-to-root poplar. This unfavorable endogenous hormone profile may contribute to the recalcitrance of rooting in American chestnut and yellow camellia cuttings. In this study, we found that the vascular cambium region in American chestnut cuttings was the least active and most condensed, with clusters of active cell division not presenting until 48 days after excision and auxin induction. American chestnut stems possess a closed sclerenchyma ring, while sclerenchymata in yellow camellia, poplar hybrids (Populus spp.), and weeping willow (Salix babylonica L.) cuttings are dispersed. Promoter analysis of an adventitious root-promoting gene, AINTEGUMENTA, showed that the number of auxin-responsive cis-elements in poplar is at least three times greater than in American chestnut, likely contributing to the contrasting rooting response with auxin between the two species. Compared to 1-naphthaleneacetic acid, a slow-release synthetic auxin, 4-chlorophenoxyacetic acid-l-tryptophan-OMe, induced more adventitious roots in American chestnut cuttings.

Species used in this study: American chestnut [Castanea dentata (Marshall) Borkh.], poplar hybrids ‘Ogy’ [Populus × euramericana (Dode) Guinier] and 717-1B4 (P. tremula L. × P. alba L.), weeping willow (Salix babylonica L.), yellow camellia (Camellia nitidissima Chi.).

Chemicals used in this study: 1-Naphthaleneacetic acid (NAA), 4-chlorophenoxyacetic acid–l-tryptophan-OMe.