Conservation Biological Control in strawberries

SANCHEZ, NORMA; GUGOLE OTTAVIANO, MF ; GRECO NANCY; CÉDOLA, CLAUDIA; LILJESTHROM, GERARRDO

Montenegro

Simposio; II Congreso Latinoamericano de Acarología; 2016

Sociedad Latinoamericana de Acarología

Tetranychus urticae (Acari: Tetranychidae) is the main pest in strawberry crops (Fragaria x ananassa) grown in horticultural areas surrounding La Plata (Buenos Aires, Argentina), and its control is mainly performed using acaricides. This area display a diverse mosaic of crops and wild vegetation like Urtica urens, Lamium amplexicaule, Convolvulus arvensis, Sonchus oleraceous, Galega officinalis that provide shelter and food resources for natural enemies in different seasons. Neoseiulus californicus (Acari: Phytoseiidae), of wide distribution in Argentina, is spontaneously present in the orchards and is the most important natural enemy of T. urticae . This predator, has a high spatial coincidence with T. urticae; the ability to feed on other sources such as pollen of some weeds; the capacity of starvation under adverse conditions; a long longevity, and the capacity to reproduce during winter. All these attributes promote the persistence of N. californicus in the environment and contribute to the early colonization of strawberry crops. Considering that N. californicus is a promising natural enemy to implement a Conservation Biological Control of T. urticae, and with the objective to reduce the use of acaricides in strawberry crops, we developed a management plan for T. urticae. This consists of using a sampling plan (systematic presence-absence sampling) of active T. urticae and N. californicus, and a decision chart to help to decide one of the following strategies: 1) to use a selective acaricide and to sample again at 7 days, 2) no action and to sample again at 7 days, 3) no action and to sample again at 14 days. This plan appear to comply with the proposed objective and is feasible and useful for growers.