This chapter presents an overview on the hypotheses for the development of the new rotation-tolerant Western corn rootworm (WCR) variant, attraction of different crops to WCR adults and their feeding on non-maize crops, development of WCR adults in maize following different crops, and population level of WCT adults in different crop stands in the USA. Results are also presented of an experiment conducted in Hungary in 2000.

1 Field studies on the efficacy of entomopathogenic nematodes as biological pest control agents in field crops and over multiple seasons are rare. 2 In the present study, we investigated the efficacy of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) at reducing maize root damage caused by the larvae of the western corn rootworm Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). The study consisted of 21 field-scale experiments in Hungary conducted between 2004 and 2007. Key factors behind successful control, such as application techniques, nematode dosage, soil environment and rainfall, were analyzed. 3 Five of the six tested techniques for applying the nematodes using readily available farming machinery resulted in a reduction of root damage, as well as subsequent plant lodging. 4 According to damage rating with the Iowa 1-6 scale, damage was reduced by 3-18%. According to the 0.00-3.00 node injury scale, damage was reduced by 14-54%. Approximately 7-62 % of plant lodging, and thus direct yield losses as a result of in-harvestability, was prevented. 5 An increase in nematode dosage and/or an increased rainfall during the period of applications increased the efficacy of H. bacteriophora at reducing root damage. Except for the obvious effect of moisture, the soil environment had little measurable influence on nematode efficacy. 6 The present study demonstrates the potential for field-scale nematode application to significantly reduce damage caused by D. v. virgifera larvae. It is recommended that the method of agent application should be selected on a case-by-case basis considering the efficacy data presented here, the available application machinery and its associated costs.

The greenhouse whitefly (Trialeurodes vaporariorum) is a pest insect on sweet pepper (Capsicum annuum) in Hungary, but not in the Netherlands. To examine the underlying mechanism for this difference, whitefly strains from both countries were tested on commonly used Hungarian and Dutch sweet‐pepper cultivars. The developmental rate from egg to adult, the survival rate of adults and the oviposition rate were measured. For all three parameters the Hungarian sweet‐pepper cultivar turned out to be a better host plant for whiteflies than the Dutch cultivar. Also the whitefly strains differed in performance on the two cultivars. The Hungarian whiteflies showed a higher survival from egg to adult and laid more eggs per female on the Hungarian sweet‐pepper cultivar than did the Dutch whiteflies. Both factors ‐ a better adaptation of Hungarian whitefly to sweet pepper and a better host‐plant quality of Hungarian sweet pepper ‐ contribute to explain the observation that whitefly can develop to pest status in Hungary. The results lead to several conclusions: a. sweet‐pepper cultivars show different degrees of resistance to whitefly, increase in resistance of Hungarian cultivars through breeding seems promising, b. whiteflies show different degrees of adaptation to a (relatively poor) host plant, sweet pepper. The experiments were partly financed and took place within the frame‐work of a scientific exchange program between the Hungarian Ministry of Agriculture and Food and the Dutch Ministry of Agriculture and Fisheries. Zusammenfassung Zur Parasit‐Wirt‐Beziehung zwischen Encarsia formosa Gahan (Hym., Aphelinidae) und Trialeurodes vaporariorum (Westwood) (Hom., Aleyrodidae). XXIX. Über die Eignung von zwei Capsium annuum L.‐Sorten als Wirtspflanze von zwei T. vaporariorum‐Stämmen In Ungarn ist Trialeurodes vaporariorum ein Schädling an Capsium annuum, nicht aber in den Niederlanden. Um diesen Unterschied zu untersuchen, wurde jeweils ein Stamm der Weißen Fliege aus beiden Ländern auf der in Ungarn bzw. in den Niederlanden üblichen Paprikasorte angesetzt. Es wurden die Entwicklungsdauer (Ei‐Imago), die Überlebensrate der Adulten und die Eiablagerate bestimmt. Bezüglich aller drei Parameter erwies sich die ungarische Paprikasorte gegenüber der holländischen als die besser geeignete Wirtspflanze. Auch die T. vaporariorum‐Stämme unterschieden sich hinsichtlich ihrer Leistungen auf den beiden Paprikasorten. Der ungarische Stamm hatte im Vergleich zum holländischen auf der ungarischen Paprikasorte eine höhere Überlebensrate, und die Weibchen legten mehr Eier ab. Beide Faktoren ‐ die bessere Adaptation der ungarischen Weißen Fliege und die bessere Eignung des ungarischen Paprikas als Wirtspflanze ‐ können die Beobachtungen erklären, daß die Weiße Fliege in Ungarn ein Paprikaschädling ist. Diese Ergebnisse führen zu folgenden Schlußfolgerungen: a. verschiedene Paprikasorten weisen eine unterschiedliche Resistenz gegenüber der Weißen Fliege auf, eine Resistenzzüchtung scheint erfolgversprechend, b. die Weiße Fliege hat sich u...

The area of protected crops in Hungary is about 5300 ha. Most of it is under plastic, the area under glass being only about 250 ha. Vegetable growing makes up 80%, mostly on private farms. The main crops are capsicum, tomato and cucumber. On relatively small areas, ornamentals, principally cut flowers, are produced: carnation, gerbera, rose and chrysanthemum. The three most important, commonly occurring pests are Trialeurodes vaporariorum, Tetranychus urticae and aphids (Aphis gossypii, Myzus persicae, A. nasturtii). Polyphagotarsonemus latus, Liriomyza trifolii and Aculops lycopersici caused considerable economic damage during the eighties. However, in the last few years these pests have not been observed in any crops. Two new glasshouse pests have been described from ornamentals during the last 2 years in Hungary: Frankliniella occidentalis and Bemisia tabaci. Their accidental appearance in vegetable crops could lead to direct economic loss, besides endangering biological control systems.