A decision algorithm for patch spraying

It has been established that weeds are spatially aggregated with a spatially varying composition of weed species within agricultural fields. Site‐specific spraying therefore requires a decision method that includes the spatial variation of the weed composition and density. A computerized decision method that estimates an economic optimal herbicide dose according to site‐specific weed composition and density is presented in this paper. The method was termed a ‘decision algorithm for patch spraying’ (DAPS) and was evaluated in a 5‐year experiment, in Denmark. DAPS consists of a competition model, a herbicide dose–response model and an algorithm that estimates the economically optimal doses. The experiment was designed to compare herbicide treatments with DAPS recommendations and the Danish decision support system PC‐Plant Protection. The results did not show any significant grain yield difference between DAPS and PC‐Plant Protection; however, the recommended herbicide doses were significantly lower when using DAPS than PC‐Plant Protection in all years. The main difference between the two decision models is that DAPS integrates crop–weed competition and estimates the net return as a continuous function of herbicide dose. The hypothesis tested is that the benefit of using lower herbicide doses recommended by DAPS would disappear after a few years because weed density will increase and thus require higher doses. However, the results of weed counting every year did not confirm this hypothesis.     

Real-time weed detection, decision making and patch spraying in maize, sugarbeet, winter wheat and winter barley

Information on temporal and spatial variation in weed seedling populations within agricultural fields is very important for weed population assessment and management. Most of all, it allows a potential reduction in herbicide use, when post‐emergence herbicides are only applied to field sections with weed infestation levels higher than the economic weed threshold; a review of such work is provided. This paper presents a system for site‐specific weed control in sugarbeet (Beta vulgaris L.), maize (Zea mays L.), winter wheat (Triticum aestivum L.) and winter barley (Hordeum vulgare L.), including online weed detection using digital image analysis, computer‐based decision making and global positioning systems (GPS)‐controlled patch spraying. In a 4‐year study, herbicide use with this map‐based approach was reduced in winter cereals by 60% for herbicides against broad‐leaved weeds and 90% for grass weed herbicides. In sugarbeet and maize, average savings for grass weed herbicides were 78% in maize and 36% in sugarbeet. For herbicides against broad‐leaved weeds, 11% were saved in maize and 41% in sugarbeet.     

植物检疫除害处理研究进展

对国内近年植物检疫除害处理技术几个方面的研究进行了综述,从总体看,高效、环保除害技术是未来植物检疫除害处理技术研究的基本要求和发展方向。     

刺桐姬小蜂的发生、危害与检疫

刺桐姬小蜂是一种新入侵的有害生物,专一危害刺桐属植物。近两年陆续在美国夏威夷、中国台湾等地严重发生,2005年7月中国大陆首次发现该虫。本文分别介绍了刺桐姬小蜂的发生、传播、危害、鉴定、生物学特性和防控检疫等。     

椰心叶甲生物学特性及其防治研究进展

介绍了椰心叶甲的生物学特性、检疫及对其化学、生物防治的研究进展。加强植物检疫是控制其传播的有效手段,综合防治才能控制椰心叶甲的危害。     

Practical experiences with a system for site-specific weed control in arable crops using real-time image analysis and GPS-controlled patch spraying

Information on temporal and spatial variation in weed seedling populations within agricultural fields is very important for weed population assessment and management. Primarily, spatial information allows a potential reduction in herbicide use, when post‐emergent herbicides are only applied to field sections with high weed infestation levels. This paper presents a system for site‐specific weed control in sugar beet, maize, winter wheat, winter barley, winter rape and spring barley. The system includes on‐line weed detection using digital image analysis, computer‐based decision making and Global Positioning System‐controlled patch spraying. In a 2‐year study, herbicide use with this map‐based approach was reduced in winter cereals by 6–81% for herbicides against broad leaved weeds and 20–79% for grass weed herbicides. Highest savings were achieved in cereals followed by sugar beet, maize and winter rape. The efficacy of weed control varied from 85% to 98%, indicating that site‐specific weed management will not result in higher infestation levels in the following crops.     

Propylene oxide: A potential quarantine and pre-shipment fumigant for disinfestation of nuts

Propylene oxide (PPO) was evaluated at a low pressure of 100 mm Hg for toxicity to different life stages of the Indianmeal mothPlodia interpunctella (Hübner) in the presence and absence of three species of nuts. Eggs and larvae were generally the most tolerant life stages in empty chambers and on the nut crops. Complete mortality of all life stages was achieved at a concentration x time (CT) product of 61.2 mg hl ⁻¹ for empty space fumigation. Dosages of 13.9, 60.3, 72.1 and 93.1 mgl ⁻¹ were required to kill 99% of the larvae when fumigation of 4-h duration took place in an empty chamber and in the presence of peanuts, almonds and walnuts, respectively. After an initial dose of 68.7 mgl ⁻¹ and a 5-h exposure time, sorption of PPO by peanuts, almonds and walnuts was relatively high, ranging from 87% of the initial concentration for peanuts to 91% for walnuts. PPO residues measured in peanuts, almonds and walnuts were 111, 46 and 80 ppm, respectively, 1 day after termination of fumigation. All of these values were below the 300 ppm maximum tolerance set by the FDA of the United States. These data show that the combination of PPO and low pressure has the potential to replace methyl bromide fumigation for quarantine and pre-shipment purposes. http://www.phytoparasitica.org posting July 22, 2006     

进口植物及植物产品有害生物风险分析

本文从经济、生态和人及人类社会3个方面阐述了外来有害生物的风险;根据国际标准中制订的有害生物风险分析流程,定性地描述了有害生物风险分析的方法;并从入侵种特性研究、适生区预测研究和风险分析模型3个方面阐述了有关有害生物风险分析的理论研究进展,这些理论研究有助于为有害生物风险定量分析提供科学依据。     

引诱剂对两种外来白蚁的引诱作用

利用白蚁喜食的植物和添加剂等配制了4种白蚁诱饵并在进口木材上进行了诱捕试验，筛选出了效果较好的2种配方。并对其在木材白蚁检疫中的应用进行了探讨。