Green Cane Harvest Effect on Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae) Larvae Abundance and Losses Caused by This Pest in Tucumán, Argentina

Abstract

From 2010 to 2012 harvest seasons, studies of the armyworm Pseudaletia unipuncta were conducted in sugarcane in Tucuma ´n. The larvae are nocturnal and during the day remain hidden under the crop residues or in the soil. Damage begins in spring when temperature rises. They produce damage by feeding and killing the shoots, delaying the growth of the new shoots in the cane field. This study aimed to evaluate the effect of agricultural residues of sugarcane green harvest on larval abundance and the losses caused by this armyworm. Trials were conducted at three locations. Twelve points of 2 m row length were evaluated every 15 days from September to November. The number of larvae and percentage of affected shoots were evaluated. When the attack of P. unipuncta began in September, a plot of 1 ha was sprayed with pesticides, and another plot was left with harvest residues and the pest. Five samples of 10 stalks were extracted per plot. Factory parameters (pol, brix) were evaluated in the lab. Localities averaged shoot losses between 13 and 30 %. The average relative abundance of larvae in the plots with harvest residues was 0.5 larvae per 2 m row; no larvae were found in plots without residues. Factory sugar yield was 10.7 % in the plot without insecticidal control and 12 % in the treated plot, with a total sugar loss of 23.2 % per ha. To prevent losses caused by this species, it is important to sample early green cane harvested fields in spring.

Unraveling the population structure of Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) in Argentina

“…In Argentina, the main host plants of this species vary according to each region. In the north western region, it causes significant losses mainly in sugarcane (Willink 1982;Salvatore et al, 2010). However, in the Pampean region, the main host plant is corn, followed by sorghum and wheat (Aragón 2002;Iannone 2002;Serra & Trumper, 2006), whereas in the Mesopotamian region, it produced significant losses to rice crop (Anglada & Del Porto, 2006).…”

Identification of male-produced aggregation pheromone of the curculionid beetle Acrotomopus atropunctellus

“…The phylogeny relationship between the taxonomic positions was genetically established by Marvaldi et al (2002) and confirmed by Bouchard et al (2011). A decade ago, this species has been detected across all sugarcane ( Saccharaum officinarum ) planting areas in the Argentinean Northwest with increasing population densities, raising concerns about potential economic impact on sugarcane production that exceeds 250 000 ha (Salvatore et al , 2009). Sugarcane plants are 2–6 m tall forming dense bushes; while, the adult weevils are small (9–12 mm long) and present a similar coloration that cane, making them hard to observe in the field.…”