Platyedra

Agricultural fields and cultivated areas; species-specific associations with host plants including cotton (Gossypium) and hollyhock (Alcea rosea). Platyedra gossypiella occurs in irrigated cotton-growing regions in arid to semi-arid climates. Platyedra malvella is associated with gardens and areas where hollyhocks are cultivated.

Europe (including Great Britain, Scandinavia, Denmark, Norway, Sweden); Africa (Sudan); Asia. Distribution varies by species: Platyedra malvella expanded from southeastern England northward to Scotland by 1937. Platyedra gossypiella has been documented in Northern Sudan.

Platyedra malvella: adults on the wing late June to early August (single generation per year in some populations, two generations reported in others). Platyedra gossypiella: moth emergence from diapausing larvae occurs at or near the lowest atmospheric water vapour saturation deficit of the year.

Seed-feeding: Platyedra gossypiella feeds on cotton seeds within bolls; Platyedra malvella feeds on hollyhock (Alcea rosea) seeds within capsules. One record of P. malvella on cotton.

• Gossypium - hostcotton seeds in bolls; primary host for P. gossypiella
• Alcea rosea - hosthollyhock seeds in capsules; primary host for P. malvella
• Althaea officinalis - hostmarsh mallow; recorded host for P. malvella

Larval development occurs within seed capsules or cotton bolls. Full-grown larvae descend to soil to pupate (P. malvella) or enter diapause (P. gossypiella). Platyedra gossypiella exhibits facultative larval diapause influenced by atmospheric water vapour saturation deficit during larval development; well-fixed diapause lasts until saturation deficit falls, poorly-fixed diapause breaks immediately. Platyedra malvella: larvae overwinter in cocoons in soil, become active in May, tunnel through soil, and pupate in late May to June.

Larvae feed concealed within seeds. When disturbed, P. malvella larvae wriggle backward out of capsules and drop to ground on silken threads. Adults of P. malvella are crepuscular and can be disturbed from vegetation in evening. Rapid crop maturity in cotton allows escape from serious P. gossypiella damage.

Seed predator; agricultural pest causing economic damage to cotton and ornamental hollyhock production. Platyedra gossypiella caused 10.7% yield loss (135 pounds seed cotton per acre) in Northern Sudan in 1948, with disproportionate damage to late-ripening top crop (33.3% loss) versus early bottom crop (3.5% loss).

Significant agricultural pest of cotton (P. gossypiella, Pink Bollworm) and ornamental hollyhock (P. malvella). Management strategies include rapid crop maturity and even growth to escape damage, and attention to seedling pest damage that may predispose crops to increased bollworm attack. No conclusive evidence for local carry-over as sole source of initial infestation in P. gossypiella.

• Earias insulanaSpiny Bollworm; co-occurs as cotton pest in Sudan, causing similar boll damage but distinguished by morphological differences and lower damage levels (2.2% vs 10.7% yield loss in 1948 study)
• Pectinophora gossypiellaPink Bollworm; former name for Platyedra gossypiella, now synonymized but may appear in older literature

• agricultural pest
• seed predator
• cotton pest
• hollyhock pest
• diapause
• Gelechiidae

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Pink Bollworm, Platyedra gossypiella (Saund.), as a Pest of Cotton at Zeidab, Northern Sudan
• THE HOLLYHOCK SEED MOTH (PLATYEDRA MALVELLA HÜBN.), TOGETHER WITH NOTES ON THE DISTRIBUTION OF APION RADIOLUS KIRBY AND AN ASSOCIATED GLINODIPLOSIS SPECIES