Ovipositional Preference and Larval Performance of the Banded Sunflower Moth (Lepidoptera: Tortricidae) and Its Larval Parasitoids on Resistant and Susceptible Lines of Sunflower (Asterales: Asteraceae)

Abstract

Banded sunflower moth, Cochylis hospes Walsingham, is one of the most destructive seed-feeding insect pests of sunflowers, causing significant economic yield losses in the northern Great Plains. In an attempt to understand host-plant resistance mechanisms for this pest, we field-tested, over several years, the effects of seven sunflower accessions, rated as resistant to C. hospes in previous screening trials, and a susceptible control (Par 1673-2), on the ovipositional preference and larval performance of C. hospes and its larval parasitoids. Of the resistant accessions, PI 494859 was the most preferred for oviposition, receiving a significantly greater number of eggs per head than did the susceptible Par 1673-2 in 2 of 3 yr. However, the numbers of larvae, and consequently the rate of seed infestation, found in PI 494859 heads were significantly lower than those in Par 1673-2 heads over all 3 yr. Female moths laid relatively few eggs on accessions PI 170385, 291403, and 251902, compared with on Par 1673-2, resulting in lower numbers of larvae per head and lower percentages of seed damaged. No association was observed between the concentrations of two diterpenoid alcohols or two diterpenoid acids in sunflower bracts and the numbers of eggs laid on the heads of the accessions. The number of banded sunflower moth larvae and the proportion of seeds damaged were positively correlated with kaurenoic acid concentrations and negatively correlated with kauranol concentrations. A positive association between resistance to larval feeding and parasitism was found in years 2006 and 2008, with resistant accessions having significantly greater proportions of parasitized larvae than did the susceptible Par 1673-2.

Ethnobotany and the Role of Plant Natural Products in Antibiotic Drug Discovery

“…This class of diterpenoids occurs in many plant families, including Asteraceae, Annonaceae, Apiaceae, Celastraceae, Chrysobalanaceae, Erythroxylaceae, Euphorbiaceae, Fabaceae, Lamiaceae, Jungermanniaceae, Rhizophoraceae, Rutaceae, and Velloziaceae . Kaurenoic acid is an intermediate for many other diterpenoids, including the gibberellins, a class of plant hormones involved in development. , Many bioactivities have been attributed to kaurenoic acid, including antidiabetic properties, genotoxicity against some tumor cells, − antifungal activity against Trichophyton rubrum , T. metagrophytes , and Epidermpphyton floccosum and as a phagostimulant . It has also shown activity against the botanical gray mold, Botrytis cinerea.…”

“…381,382 Many bioactivities have been attributed to kaurenoic acid, including antidiabetic properties, 383 genotoxicity against some tumor cells, 384−386 antifungal activity against Trichophyton rubrum, T. metagrophytes, and Epidermpphyton f loccosum 387 and as a phagostimulant. 388 It has also shown activity against the botanical gray mold, Botrytis cinerea. 389 A 2007 review of the kaurane diterpenoids discusses their bioactivities and synthesis in detail.…”

Relative susceptibility of sunflower maintainer lines and resistance sources to natural infestations of the banded sunflower moth (Lepidoptera: Tortricidae)

“…Charlet et al (2009) evaluated resistance for H. annuus obtained from the United States National Plant Germplasm System (NPGS) using natural infestations; relative to the 25 interspecific crosses evaluated, several H. annuus entries from NPGS (abbreviated PI for "Plant Introduction" number) were found with equal or lower damage from banded sunflower moth feeding over five years. Additional research on some of these entries found evidence of decreased larval survival, but no chemical or physical cause of the antibiosis could be determined (Chirumamilla et al 2014).…”

“…Additional research on some of these entries found evidence of decreased larval survival, but no chemical or physical cause of the antibiosis could be determined (Chirumamilla et al . 2014).…”

Registration of oilseed sunflower maintainer germplasm HA 489 with resistance to the banded sunflower moth

“…Among the most important of these head‐feeding pests in North America is the banded sunflower moth ( Cochylis hospes Walsingham [Lepidoptera: Tortricidae]) (Charlet & Busacca, 1986; Rogers, 1988; Knodel & Charlet, 2007). The banded sunflower moth is especially concerning as a pest due to its ability to overwinter in the northern Great Plains, which several other prominent insect pests of Helianthus are unable to do (Chirumamilla et al., 2014). As a result, the banded sunflower moth is one of the most consistent insect pests of Helianthus in North Dakota and South Dakota, which together account for over 75% of U.S. sunflower production (USDA National Agricultural Statistics Service, 2018).…”