Macadamia Felted Coccid (MFC), Acanthococcus ironsidei (Williams) (Hemiptera: Eriococcidae) was first discovered in 2005 on the Island of Hawaii. Host plants are restricted to Macadamia species, with Macadamia integrifolia Maiden & Betche (Proteaceae) being grown in Hawaii for nut production. Approximately 16,900 acres of macadamia nuts are harvested in Hawaii with estimated farm value of $ 48.8 million (2019 - 2020 records). MFC has become a problem in macadamia orchards where heavy infestations cause the death of young seedlings, reduction in nut production, and severe damage can eventually kill affected trees. Chemical control and extant natural enemies have not suppressed the population of MFC to a manageable level. Exploration in Australia started in November 2013 for the evaluation of potential parasitoids being host specific for introduction into Hawaii. A dominant solitary endoparasitoid of MFC from New South Wales was discovered and described as Metaphycus macadamiae Polaszek & Noyes sp. n (Hymenoptera: Encyrtidae: Encyrtinae). Biology and host specificity testing were conducted at the Hawaii Department of Agriculture, Insect Containment Facility on nine Hemipteran and three Lepidopteran eggs. Results indicated that M. macadamiae is host specific to MFC. There has been no evidence of parasitism or host feeding on any of the non-target insect hosts that were tested. Parasitoid emergence from the control (MFC) averaged 30.2% compared to 0% on non-target hosts. Low rate of parasitoid emergence in the laboratory (average 30.2 %), and increased rate of MFC nymphal mortality was due to adult feeding. Percent field parasitism reached up to 32.7% emergence in the NSW Alstonville, Australia. We report on the parasitoid performance in native Australia, rearing biology, host specificity testing, and the extant natural enemies associated with MFC in Hawaii. A petition to release this parasitoid for the biocontrol of MFC in Hawaii is pending. Once permitted for release, the colony will be shared with South African Mac Nut Association for their biocontrol program of this invasive pest. They will conduct their own testing before approval for release.

The global production of macadamia nuts has witnessed a significant increase, resulting in the accumulation of large quantities of discarded nutshells. These nutshells possess remarkable hardness and toughness, comparable to aluminum. Incorporating natural fillers to enhance the properties of composite materials for various applications, including light duty, structural, and semi-structural purposes, is a common practice. Given their inherent hardness and toughness, macadamia nutshells present an intriguing choice as fillers, provided that the manufacturing conditions are economically viable. With the urgent need to shift towards natural fillers and reduce reliance on synthetics, exploring macadamia nutshells as components of natural fiber composites becomes imperative. This review aims to comprehensively examine the existing body of knowledge on macadamia nutshells and their bio-synthetic polymer composites, highlighting key research findings, achievements, and identifying knowledge gaps. Furthermore, the article will outline prospective areas of focus for future research endeavors in this domain, aligning with the universal goal of minimizing synthetic materials.

Macadamia nut plantings in China are expanding year by year. In order to further promote the superior varieties, this study analyzed the effects of different varieties of rootstock and scion on the survival rate as well as the effects of 18 different ratios of substrate composition on seedling growth were analyzed. The results showed that: The survival rate of HAES788 varieties as rootstock and Guire No.1 as scion was the highest, reaching 96%. The optimal grafting time in December was better than that in March. Substrate formulations 12, 13, 15 and 16 had agglomerated soil and well-developed root systems compared to the controls. Plant height, stem diameter, leaf length, leaf width, and dry weight of aboveground and underground parts were significantly higher than those of the control. In addition, the substrate formulations 12, 13, 15 and 16 significantly improved the organic matter, total nitrogen, and total potassium content of the substrate soils, but little on total phosphorus content. All in all, macadamia grafting times are best in December, with HAES788 and Guire No.1 being the best rootstock and scion. Substrate formulations 12, 13, 15 and 16 are the optimal formula. This study provides a solid foundation to produce high-quality macadamia seedlings.

Macadamia (Macadamia integrifolia) nuts have become an essential commodity crop in Malawi. The nuts are a lucrative commodity and are used for household consumption and income generation among farming families and as a foreign exchange earning crop at country-level. In addition, macadamia production has increased significantly in recent years in the country. Currently, Malawi is the seventh top producer of macadamia nuts, with a global market share of three percent (1,846 metric tonnes on kernel basis). In 2018, exports of macadamia kernel had a value of US$24.3 million (£19.8 million or MKW 18.01 billion). However, the bulk (85%) of the crop is grown on large commercial plantations, but the smallholder sector is emerging as vital for the future growth of the macadamia sub-sector in Malawi. Furthermore, Malawian smallholders consider macadamia production to be a low-input crop with large returns per unit area (US$14.37 kg^-1ha^-1 or MKW 10,701kg^-1ha^-1) thus a lucrative crop with high potential for poverty reduction and wealth creation among these farming families. This paper, therefore, explores: (i) the historical and current trends in macadamia nut production in Malawi; (ii) analyses the country’s macadamia value chain and (iii) discusses the constraints of macadamia production in Malawi for informed policymaking. Thus, the synthesis of the Malawian macadamia sub-sector provides an understanding of the vital contributions of macadamias to Malawi’s economic growth and improvement of livelihoods.