European Corn Borer (Lepidoptera: Crambidae) Infestation Level and Plant Growth Stage on Whole-Plant Corn Yield Grown for Silage in Virginia

Abstract

Field experiments were conducted in 2004 and 2005 to determine the effect of different levels of hand-infested third instar European corn borer, Ostrinia nubilalis (Hiibner) (Lepidoptera: Crambidae), on whole-plant yield and plant growth stage in corn, Zea mays L., grown for silage. In 2004 and 2005, European corn borer infestation level had a significant negative impact on whole-plant yield (grams of dry matter per plant) with increasing infestation; however, whole-plant yield was not significantly affected by plant growth stage in either year. In 2004, the six larvae per plant treatment caused the greatest percentage of reduction (23.4%) in mean (+/-SEM) whole-plant yield (258.5 +/- 21.0 g dry matter per plant) compared with the Bacillus thuringiensis (Bt) CrylAb control (337.3 +/- 11.1 g dry matter per plant). In 2005, the five larvae per plant treatment caused the greatest percentage of reduction (8.3%) in mean whole-plant yield (282.3 +/- 10.8 g dry matter per plant) compared with the Bt CrylAb control (307.8 +/- 8.3 g dry matter per plant). The relationship between mean whole-plant yield and European corn borer larvae infestation level from the pooled data of both years was described well by using an exponential decay model (r2 = 0.84, P = 0.0038). The economic injury level for silage corn was estimated to be approximately 73% higher than for corn grown for grain based on similar control costs and crop values. In addition, plant growth stage and European corn borer infestation level had no effect on percentage of acid detergent fiber, neutral detergent fiber, and crude protein values in either year of the study.

A Technique Using Reusable Components for Hand-Infesting Cornstalks With European Corn Borer (Lepidoptera: Crambidae) Larvae

“…Our study was a separate part of an ongoing European corn borer yield study conducted by Tiwari et al (2009a). The gelatin capsule technique described by Bode and Calvin (1990) was compared with a technique using reusable plastic wire connectors (the wire nut technique).…”

“…The wire nut used in the study is a #86 (medium) WingGard (Gardner Bender, Milwaukee, WI) electrical wire connector. The experiment, as described by Tiwari et al (2009a), consisted of a splitplot randomized complete block design, with blocks replicated eight times during both years. Each block consisted of three main plots with each main plot representing one of the following plant growth stages: 10-leaf, 16-leaf, and blister.…”

Aras kerusakan ekonomi (AKE) larva Ostrinia furnacalis (Lepidoptera: Crambidae) pada tiga fase pertumbuhan tanaman jagung

“…Semua tingkat infestasi digunakan larva instar III karena larva instar III yang mulai menggerek batang (Jordan 2008;Tiwari et al 2009). …”

“…Ujung tabung lainnya ditutup dengan menggunakan tutup botol diameter 1,1 cm. Metode ini merupakan modifikasi dari metode wire-nut oleh Tiwari et al (2009).…”

European corn borer injury effects on lignin, carbon and nitrogen in corn tissues

“…Pascholati et al (2008) reported increased levels of phenylalanine ammonia-lyase (PAL), the first enzyme in phenylpropanoid biosynthesis pathway, in corn mesocotyls that were wounded by rubbing with Al 2 O 3 but did not assess lignin production. Tiwari et al (2009) reported no effect of ECB infestation level, with up to six larvae per plant, on acid detergent fiber of whole corn plants at the half kernel milkline stage. Therefore, injury can indirectly lead to lignin deposition through fungal infections but whether herbivore injury acts as a direct stimulus to stress-induced lignin or lignin-like deposition in corn tissues is not yet well known.…”