In South East Queensland, Australia, Brassica crops are typically attacked by Crocidolomia pavonana Fabricius (Lepidoptera: Crambidae) in late summer and autumn (February to May) and by Plutella xylostella L. (Lepidoptera: Plutellidae) and Pieris rapae L. (Lepidoptera: Pieridae) from late autumn to the end of spring (May to November). Physical exclusion studies were used to assess the impact of predators on pest populations in two cabbage [Brassica oleracea L. var. capitata cv. Warrior (Brassicaceae)] crops grown sequentially between April and September 2006. The studies were complemented by molecular gut-content analysis of predators simultaneously hand-collected from the study crops by destructive sampling of cabbage plants. In May 2006, exclusion studies showed that 57% (95% CI = 40-74%) of the C. pavonana study cohort was lost to predation. Spiders represented 81% of all predators collected and Lycosidae collected from the soil surface beneath sampled plants dominated (61% of predators); 23% of Lycosidae contained C. pavonana DNA, whereas 5% contained P. xylostella DNA. In August 2006, exclusion studies showed that 88% (95% CI = 83-93%) of the P. xylostella cohort was lost to predation. Spiders represented 99% of all predators collected; soil surface dwelling Lycosidae (51% of predators) dominated, followed by Linyphiidae (20%) and foliar-dwelling spiders (16%; Theridiidae, Salticidae, Clubionidae/Miturgidae, and Oxyopidae combined); 12% of Lycosidae and 38% of foliar-dwelling spiders contained P. xylostella DNA. Life tables for P. xylostella that were constructed for cohorts exposed to predators and cohorts from which predators had been physically excluded showed that eggs and neonates suffered the highest rates of predation. In a concurrent study, P. xylostella that were naturally recruited to the field population suffered similar high levels of early-stage mortality.

The fruit borer (Helicoverpa armigera Hubner) is one of the key pests of chili pepper in Indonesia. Yield loss due to this insect pest may reach up to 60%. Chemical treatment for controlling this insect pest is ineffective and eventually leads to environmental pollution. More environmentally safe insecticides are developed based on natural plant ingredients as their active compound such as essential oils. This study aimed to assess the potential of citronella oil for managing H. armigera on chili pepper. The experiments were conducted at the Indonesian A field experiment was designed in a randomized complete block design with five treatments and replicated five times. Citronella oil was extracted by steam distillation from Cymbopogon nardus. The oil was then chemically characterized by using GC-MS and its efficacy (ovicidal and feeding deterrent) against H. armigera was tested both in laboratory and field conditions. The GC-MS result showed that major chemical compounds of the citronella oil used were citronella (35.97%), nerol (17.28%), citronellol (10.03%), geranyle acetate (4.44%), elemol (4.38%), limonene (3.98%), and citronnellyle acetate (3.51%). The laboratory experiment revealed that the highest concentration (4,000 ppm) of citronella oil reduced egg laying by 53-66%. Ovicidal activity was concentration dependent, and egg hatchability decreased by 15-95% compared to control. The field experiment showed that treatment of citronella oil at 2.0 mL L -1 significantly reduced fruit damage by H. armigera similar to the plots treated with spinosad at the recommended dose (60 g ai ha -1 ). Application of citronella oil significantly reduced fruit damage by 72% and increased quality of the chili pepper. Because oviposition and feeding deterrent properties are key factors in controlling the pest, therefore this study revealed that citronella oil has potential to be incorporated into the controlling program of H. armigera on chili pepper.

In Indonesia, the chili (Capsicum annuum L.) is popular. Unfortunately, its current productivity is lower than its potential yield. The low productivity is due to the cultivation methods or varieties used in the field. Seaweed is a known bio-stimulant and combining it with a microbial consortium could be an effective way to boost crop productivity. The goal of this study was to examine how a combination of bio stimulants enriched with a microbial consortium can affect the productivity of two chili varieties, Tanjung-2 and Ciko. The experiment used a complete randomized block design with a single factor, namely a combination of bio-stimulants (B1-B6). In comparison to other formulas, the bio-stimulant B4 formula was found to be the most effective. Keywords: bio stimulant; chili; endophytic microbial consortium; seaweed

Plutella xylostella L (Lepidoptera: Plutellidae) and Crocidolomia pavonana F (Lepidoptera: Crambidae) are serious pests of Brassica crops in the highlands of West Java, Indonesia, where they co-occur, and in Southeast Queensland, Australia where C. pavonana is a serious pest early in the crop season (February-May) and P. xylostella is a pest later in the year (June-November). Introductions of parasitoids of P. xylostella, especially Diadegma semiclausum Hellén (Hymenoptera: Ichneumonidae), have had considerable success in both countries, but no effective larval or pupal parasitoids of C. pavonana are known. The use of insecticides to manage C. pavonana disrupts P. xylostella parasitoids, leading to pest outbreaks. Thus, an integrated pest management (IPM) strategy, that takes account of both pests, is needed in both regions. Although P. xylostella parasitoids have been the centre of much research over the past 50-60 years, the impact of predatory arthropods on pest populations has received much less attention. Similarly, little is known about the impact of predators on C. pavonana populations and it appears to be attacked by a particularly sparse parasitoid fauna. In recent years, considerable advances have been made in the development of DNA-based molecular techniques to detect the remains of insect prey within the guts of predatory arthropods. However, the methods have rarely been applied in conjunction with field experiments that measure the impact of natural enemies on pest/ prey populations. In this research, field studies used a combination of ecological (natural enemy exclusion experiments and the construction of life tables) and DNA-based molecular methods to quantify the impact of predatory arthropods on P. xylostella and C. pavonana populations and to identify the most important predatory groups preying on these insect pests in the different agro-ecosystems of Queensland and West Java. The specificity of previously designed primer sequences for P. xylostella, C. pavonana and Pieris rapae L. (Lepidoptera: Pieridae) mtCO1 DNA was confirmed by testing them against a wide range of herbivores and predatory arthropods collected from the field in both West Java and Queensland. Based on field studies, key groups of predators were selected to determine the detectability half-life of target P. xylostella and C. pavonana mtCO1 DNA in their guts following consumption of single prey items. For the P. xylostella mtCO1 DNA, when tested at 25 °C the detectability half-life (DHL) was lowest in Clubionidae (18 h) < Linyphiidae (42 h) ≤ Lycosidae (61 h) < Theridiidae (135 h). Similarly when tested at this temperature, the DHL for C. pavonana mtCO1 DNA was lower in Lycosidae (93 h) than in Theridiidae (193 h). Despite having a longer base pair sequence, the target C. pavonana fragment (276 bp) typically persisted for longer in the guts of predators than iii the P. xylostella fragment (165 bp) and in Theridiidae, the DHL of target DNA of both species decreased with increasing temperature when tested at 20, 25 and 30 °C Fiel...

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