Degree-day models for predicting adult Delia platura (Diptera: Anthomyiidae) spring flight and first emergence in New York State.

The seedcorn maggot, Delia platura (Meigen), is a pest affecting many crops, including corn. The early spring emergence of adults and belowground seed damage by maggots leave no room for rescue treatments during the short growing season in New York State. Degree-day (DD) models play a crucial role in predicting insect emergence and adult peak activity and are essential for effective pest management. The current D. platura DD model was launched on the Network for Environment and Weather Applications (NEWA) in 2022, using existing scientific literature from other North American regions. The NEWA model predicted adult D. platura first emergence at an average of 471 (39°F) DD in 2022. To gain an accurate and precise understanding of D. platura adult spring emergence and activity, we used interpolated temperature data to calculate the DD for each specific location where adults were captured in the field. DD calculations were performed using the average method, setting a biofix on January 1st and a base temperature of 39°F. In 2023, overwintering adults emerged at an average of 68 DD, and in 2022, adult activity was registered at an average of 282 DD. Accurately predicting the emergence of D. platura could contribute to informing integrated pest management strategies that incorporate timing and cultural practices over chemical solutions to protect crops and the environment.

Demographic response by a small epiphytic orchid.

PREMISE OF THE STUDY: Biotic changes are an inevitable consequence of climate change. Epiphytes may be more susceptible to changes in climate variation, but data regarding responses to climate variability under field conditions are limited. We evaluated whether the abundance of demographic stages in the epiphytic orchid Lepanthes rupestris at the Luquillo Experimental Forest in Puerto Rico was associated with short-term changes in climate variation over an 8-yr period. METHODS: We used cross-correlation analyses to evaluate associations between the abundance of seedlings, juveniles, adults, and fruits per subpopulation, population growth, colonization and extinction rates in L. rupestris with variables related to precipitation and temperature, with and without lag- responses. KEY RESULTS: We detected significant negative correlations between the average number of seedlings and the number of dry days, between the average number of fruits and minimum average temperature with a 6-mo response lag, and between the average number of adults and the maximum temperature with a 1-yr response lag. Neither population growth rate nor probability of colonization and extinction were directly related to climatic variation between 2000 and 2007. CONCLUSIONS: Associations between climatic variables and demographic stages could have negative implications for this orchid within the context of expected drying trends in the Caribbean. Results argue for the establishment of long-term monitoring studies of orchid populations, because only long-term studies would provide the appropriate temporal scale to detect and predict climate change effects and adaptive management of orchid populations.