Alginate encapsulation of Begonia microshoots for short-term storage and distribution.

Synthetic seeds were formed from shoot tips of two in vitro grown Begonia cultivars using 3% sodium alginate in Murashige and Skoog medium (MS) salt solution as the gel matrix and 100 mM calcium chloride for complexation. Synthetic seed formation was achieved by releasing the sodium alginate/explant combination into 100 mM calcium chloride (CaCl2 ·H2O) solution for 30 or 45 min. Both control and encapsulated shoots were transferred into sterile Petri dishes and stored at 4°C or 22°C for 0, 2, 4, 6, or 8 weeks. Conversion of synthetic seeds into plantlets for both storage environments was assessed in MS medium or peat-based substrate. No significant difference was found between the 30 and 45 min CaCl2 ·H2O treatments or the two cultivars. Encapsulation of explants improved survival rate over time irrespective of the medium type or storage environment. Survival rates of 88, 53, 28, and 11% for encapsulated microshoots versus 73, 13, 0, and 0% for control explants were achieved in microshoots stored for 2, 4, 6, and 8 weeks, respectively. The best results were obtained when synthetic seeds were stored at 4°C and germinated on MS medium. Regenerated plantlets were successfully established in potting soil.

Eupatorium capillifolium essential oil: chemical composition, antifungal activity, and insecticidal activity.

Natural plant extracts often contain compounds that are useful in pest management applications. The essential oil of Eupatorium capillifolium (dog-fennel) was investigated for antifungal and insecticidal activities. Essential oil obtained by hydrodistillation of aerial parts was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The major components were determined to be thymol methyl ether (=methyl thymol) (36.3%), 2,5-dimethoxy-p-cymene (20.8%) and myrcene (15.7%). Antifungal activity of the essential oil was weak against the plant pathogens Colletotrichum acutatum, C. fragariae, and C. gloeosporioides in direct bioautography assay. The E. capillifolium oil showed promising repellent activity against the yellow fever mosquito Aedes aegypti, whereas the oil exhibited moderate activity against the mosquito's first instar larvae in a high throughput bioassay. Topical applications of the oil showed no activity against the blood-feeding female adults of A. aegypti. Eupatorium capillifolium essential oil showed a linear dose response between adult lace bug (Stephanitis pyrioides) mortality and increasing oil concentration in an adulticidal activity bioassay. The dog-fennel oil was more potent than the conventional insecticide malathion. In conclusion, these combined results showed Eupatorium capillifolium oil is a promising novel source of a biological insecticide with multiple modes of action.

Microdistillation and analysis of volatiles from eight ornamental Salvia taxa.

Volatile compounds from seven Salvia species and one interspecific hybrid growing at the Dallas Arboretum and Botanical Garden, Texas, US. Salvia coccinea, S. farinacea, S. greggii, S. leucantha, S. longispicata x farinacea, S. madrensis, S. roemeriana and S. splendens were investigated for their chemical compositions using a microdistillation technique. Volatiles were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). One hundred and twenty seven compounds were identified representing 94.3-99.7% of the oils. The major components in each of the seven species were as follows: S. coccinea (Z)-3-hexenal (31%), viridiflorol (19%); S. farinacea 1-octen-3-ol (30%) and (Z)-3-hexenal (23%); S. greggii 1,8-cineole (22%), borneol (17%), camphene (11%) and alpha-pinene (10%); S. leucantha limonene (35%) and alpha-pinene (17%); S. longispicata x farinacea 1-octen-3-ol (50%) and (Z)-3-hexenal (24%); S. madrensis (Z)-3-hexenal (53%); S. roemeriana limonene (49%) and alpha-pinene (20%); and S. splendens (Z)-3-hexenal (36%), 2,5-dimethoxy-p-cymene (19%) and linalool (11%). The microdistillation method was fast, practical and a useful technique that enabled the isolation of the volatiles in samples when only limited quantities were available.

Potential resistance of crape myrtle cultivars to flea beetle (Coleoptera: Chrysomelidae) and Japanese beetle (Coleoptera: Scarabaeidae) damage.

Field and laboratory studies were conducted to identify potential resistance among crape myrtles, Lagerstroemia spp., to Japanese beetle, Popillia japonica Newman and to flea beetles, Altica spp. Damage ratings revealed variation among cultivars in susceptibility to beetle feeding. Cultivars with Lagerstroemia fauriei Koehne in their parentage exhibited the least amount of damage in choice and no-choice experiments, with few exceptions. The data indicate that both beetle species cause more feeding damage on certain cultivars of Lagerstroemia indica L., such as 'Country Red', 'Twilight', and 'Carolina Beauty' than interspecific cultivars with L. fauriei in their parentage, such as 'Natchez', 'Tonto', and 'Muskogee'. When comparing the effect of parentage on all of the major pests of crape myrtle, L. faurei confers resistance to all pests except crape myrtle aphid. No correlation was found between leaf toughness, leaf color, and leaf nutrients in estimating flea beetle cultivar preference. With this information, growers can more effectively target scouting measures to the most susceptible cultivars. and breeders can select plants that will require the fewest chemical inputs.