Rowcovers and Strip Tillage Provide an Alternative to Plasticulture Systems in Summer Squash Production

Plastic mulch is often used in cucurbit production, but it has negative soil health and environmental implications due to use of tillage for installation and generation of plastic waste. This 2-year study aimed to find a viable alternative to plastic mulch through the use of strip tillage and rowcovers, as rowcovers could help minimize yield loss from strip tillage by providing warmer air and soil as well as providing insect protection. A split-plot design was used in both conventionally and organically managed summer squash (Cucurbita pepo), with production system as the whole-plot factor [conventional tillage with black plastic mulch also referred to as plasticulture (PL) and strip tillage into rolled cereal rye (Secale cereale) (ST)] and rowcover use as the subplot factor (rowcover until anthesis or no rowcover). Rowcovers reduced the incidence of squash vine borer (Melittia cucurbitae) and eliminated the need for insecticide sprays to control this insect pest, but did not reduce the incidence of yellow vine decline or the sprays needed to control squash bug (Anasa tristis). Rowcovers increased average air temperature by 1.6 to 4.0 °C and increased maximum air temperature by up to 10.3 °C. Rowcovers decreased average light intensity by 33% to 39%. Though soil temperature in PL tended to be higher than in ST, in 1-year rowcovers helped bridge the gap. Plant biomass was consistently higher in the PL than the ST system. Averaged across rowcover treatments, plants in PL had higher marketable yields than those in ST; however, the use of rowcovers often led to comparable yields between the production system treatments. Rowcover was a significant factor explaining marketable yield for the organically managed fields both years. There was no consistent effect of production system on soil microbial biomass carbon (MBC). Based on our results, strip tillage into rolled rye could be a viable alternative to plasticulture for summer squash production in Iowa, and rowcovers could help increase yields in ST especially in an organic management system.

First report of Squash Vine Borer, Melittia cucurbitae (Harris, 1828) (Lepidoptera, Sessidae) in Brazil and South America: distribution extension and geographic distribution map

Melittia cucurbitae (Harris, 1828) is a very important pest of squash and pumpkins. To date, this lepidopteran had its distribution reported for eastern United States, southeastern Canada, and Mexico. Our study reports for the first time the occurrence of squash vine borer, M. cucurbitae for South America, being the first record to Brazil, in southwest region of Pará state.

The Seasonal Occurrence of the Grape Root Borer, (Lepidoptera: Sesiidae) in the Eastern United States2

The Grape Root Borer, Vitacea polistiformis (Harris), (Lepidoptera: Sesiidae) was trapped during 1985, 1986, and 1987 in seven, nine, and 13 eastern states, respectively, with pure (E,Z)-2,13 octadecadienyl acetate or a 99:1 blend of (E,Z)-2,13 octadecadienyl acetate and (Z,Z)-3,13 Octadecadienyl acetate. The length of adult activity periods ranged from six months in Florida to two or three months in Pennsylvania, Maryland, New Jersey, and Ohio. Bimodal peaks of activity occurred most commonly in the South, and single peaks were most common in the North. Activity usually began in all states (except Central Florida) in June or early July, with principal activity occurring in August in the extreme South, in late July in the central states, and about the first of July in the northern states. In Central Florida, flight began in late July with principal activity in September. Twelve other species of sesiid moths were also collected with the sex attractant, including large numbers of Melittia cucurbitae (Harris), Paranthrene simulans (Grote), and Paranthrene asilipennis (Boisduval).

Sex Pheromone of the Female Squash Vine Borer (Lepidoptera: Sesiidae)

Analysis of ovipositor extracts of the squash vine borer Melittia cucurbitae showed that a major component in the extracts was (E,Z)-2,13-octadecadien-l-ol acetate along with traces of (Z,Z)-and (Z,E)-isomers. The extracts probably also contained (E,Z)-2,13-octadecadien-l-ol, geometrical isomers of 3,13-octadecadien-l-ol acetate, (Z)-9-hexadecen-l-ol, (Z)-9-hexadecen-l-ol acetate, (Z)-11-hexadecen-l-ol acetate, hexadecan-l-ol acetate, (Z)-13-octadecen-l-ol acetate, and (Z)-13-octadecen-l-ol. Trapping tests with permutations of these compounds showed that a binary mixture of (E,Z)-2,13-octadecadien-l-ol acetate and (Z,Z)-3,13-octadecadien-l-ol acetate (99.7:0.3) was required to effectively cause capture of males. The binary mixture proved to be more effective as a lure for squash vine borer males than (E,Z)-2,13-octadecadien-l-ol acetate alone. Thus, behavioral evidence indicated that a 2,13- plus 3,13-isomeric combination of octadecadien-l-ol acetates quite likely is a natural element in the female sex pheromone of this moth. Physical chemical evidence for the 3,13 isomer in the female extracts was equivocal because its purported occurrence was at a trace level and absolute verification of the compound's structure was not possible.

DESCRIPTION OF A NEW SPECIES OF TROCHILIUM

Trochilium Grande, n. p.—General appearance of T. Ceto (Melittia Cucurbitæ Harr.) but very much larger, expanding 1¾ inches.Antennæ blackish. Palpi reddish orange. Head white in front, dark lustrous greenish gray on top. Collar red. Thorax above dark greenish same as top of head. Abdomen red, each segment outwardly edged with black.